Fc RECEPTOR MODULATING COMPOUNDS AND COMPOSITIONS

ABSTRACT

The present invention provides compounds capable of binding to an Fc receptor and modulating Fc receptor activity comprising a core lipophilic group in the form of an Aryl zing substituted with a group rich in p-electrons. The invention further provides for a method of treating an autoimmune disease involving Fc receptor activity using such compounds. A method for obtaining a compound which modulates Fc receptor activity is also provided, the method comprising: (a) providing or designing compounds having structural characteristics to fit in the groove of the FcγRIIa structure; and (b) screening the compounds for modulating activity on the Fc receptor.

FIELD OF THE INVENTION

The invention relates to a novel class of Fc receptor modulatingcompounds. More particularly the present invention relates to apharmaceutical composition comprising an Fc receptor modulating compoundin combination with a pharmaceutically acceptable carrier.

BACKGROUND OF THE INVENTION

The immune system, once triggered by a foreign organism, responds bygenerating a series of molecules, including molecules known asantibodies, which facilitate the destruction of the foreign organism.Autoimmune diseases are a group of disorders characterised by thefailure of the immune system to distinguish between foreign and healthytissue within the body. The immune system then generates antibodies tohealthy or normal tissue including bones and joints (rheumatoidarthritis), platelets (immune thrombocytopenia purpura and bloodvessels/connective tissue (systemic lupus erythematosus).

Although the trigger for autoimmune diseases is not completelyunderstood, treatments have been developed that inhibit or halt theseverity of the damage done to healthy tissue.

Antibodies produced by people suffering autoimmune diseases bind tohealthy tissue resulting in formation of ‘immune complexes’. Theseimmune complexes bind to receptors on the surface of inflammatory whiteblood cells, called Fc receptors (FcR).

When the immune complex binds to the FcR, white blood cells areactivated releasing a series of chemicals known as cytokines into theblood system. These chemicals lead to the destruction of tissue andjoints and also propagates the immune response so that attack on healthytissue continues.

Traditional treatments, such as those for rheumatoid arthritis, includethe use of cytotoxic agents such as methotrexate. Methotrexatenon-specifically kills all dividing cells, eliminating the cellsproducing the antibodies. The major side effect of methotrexate is thatit non-specifically kills cells of the immune system leaving the patientimmuno-supressed. More recently, a number of new products have beenlaunched which inhibit the naturally produced chemicals that lead totissue/joint destruction. The limitation of some of these products isthat they target only one of the many inflammatory chemicals released.For example, Enbrel and Remicade inhibit the action of Tumour NecrosisFactor alpha (TNF) whilst Kineret inhibits Interleukin-1.

It would be understood by the person skilled in the art that althoughthe above discussion principally concerns rheumatoid arthritis, thescope of the present invention is not so limited and the scope extendsto other autoimmune diseases such as immune thrombocytopenia purpura,systemic lupus erythematosus and Crohn's disease.

The Fc receptor is a useful target for drug development because it isupstream in the inflammatory process and in theory, preventing thetriggering of this receptor should block the release of many of thetissue-damaging chemicals.

FcRs consist of a family of highly related receptors that are specificfor the Fc portion of immunoglobulin (Ig). Receptors have been definedfor each of the immunoglobulin classes and as such are defined by theclass of Ig to which they bind (e.g. Fc gamma receptors (FcγR) bindgamma immunoglobulin (IgG), Fc epsilon receptors (FcεR) bind epsilonimmunoglobulin (IgE), Fc alpha receptors (FcαR) bind alphaimmunoglobulin (IgA)). Among the FcγR receptors, three sub-familymembers have been defined; FcγRI, which is a high affinity receptor forIgG; FcγRII, which are low affinity receptors for IgG that bind toaggregates of immune complexes; and FcγRIII, which are low affinityreceptors that bind to immune complexes. In recent times, furtherdifferentiation of these receptors has been achieved, such as, forexample the identification of FcγRIIa.

These receptors are highly related structurally but perform differentfunctions. The structure and function of FcγRII is of interest becauseof its interaction with immune complexes and its association withdisease.

FcγR are expressed on most hematopoietic cells, and through the bindingof IgG plays a key role in homeostasis of the immune system and hostprotection against infection. FcγRII essentially binds only to IgGimmune complexes and is expressed on a variety of cell types including,for example, monocytes, macrophages, neturophils, eosinophils, plateletsand B lymphocytes. FcγRII is involved in various immune and inflammatoryresponses including antibody-dependent cell mediated cytotoxicity,clearance of immune complexes, release of inflammatory mediators andregulation of antibody production. The binding of IgG to a FcγR can leadto disease indications that involve regulation by FcγR. For example,thrombocytopenia purpura involves platelet damage resulting fromFcγR-dependent IgG immune complex activation of platelets or theirdestruction by FcγR+ phagocytes. In addition, various inflammatorydiseases including rheumatioid arthritis, and systemic lupuserythematosus involve IgG immune complexes.

FcγRs exist at the surface of a cell. In essence, they are dimers of twovirtually identical structures which meet in such as way that theydefine a groove. Structures of these dimers are disclosed inInternational Patent Application No. WO 99/40117. The Fc portion ofaggregated antibody binds to this groove, hence compounds designed tointerfere with the binding in the groove may inhibit antibody/receptorbinding.

Potentially suitable compounds are derived from random screening as wellas rational drug design to modulate Fc receptors. Drug design depends atleast in part on the structure of the site to which the compounds areintended to bind. U.S. Pat. No. 6,355,683 has postulated the structureof the binding region of FcγRIIa binding region based on X-raycrystallographic analysis. It is believed that the relevant binding site(that is, the groove) has a lip comprising lysine and histidine residuesand represents a target for interaction with hydrogen-bonding and/oracidic groups in a suitable modulator. The wall of the groove contains aphenylalanine benzene ring and may be a target for a hydrophobicinteraction, particularly π-π it interactions. The ‘floor’ of the grooveincludes Phe121, Thr152, Leu159 and Ser161 and together with Asn154,Lys117 (backbone carbonyl) and Thr 119. These proteins are believed tobe arranged to form a pocket that is capable of strong hydrogen bondingand/or Van der Waals interactions with a modulator or a ligand.

Because FcRs are involved in a variety of biological mechanisms, it isimportant that the compounds identified as suitable for affecting thebinding of immunoglobulins to FcγR do not adversely affect the otherbiological functions of FcRs. For example, U.S. Pat. No. 6,355,683discloses certain classes of aromatic, cyclic and amino acid speciesthat modulate binding of immunoglobulins to Fc receptors.

While many hundreds of species have been identified which affect thebinding of immunoglobulins to FcR, their binding affinity andsuitability for use in drug formulations varies. Accordingly there is anongoing need for identification of potential new chemical species thatcan be used in pharmaceutical compositions for modulation of binding ofimmunoglobulins to Fc receptors.

SUMMARY OF THE INVENTION

It has now been found that a new group or class of compounds haveactivity as Fc receptor modulating compounds and may be used inpharmaceutical compositions.

These compounds typically have a core lipophilic group, substituted witha group rich in π-electrons, preferably having a delocalised π-electronsystem. The compounds typically include at least one acidic group havinga π-electron system.

In a first aspect, the present invention provides a compound capable ofbinding to a Fc receptor and modulating Fc receptor activity having thegeneral formula I:

-   -   wherein    -   R1, R2, R3, R4, R5, are each independently selected from H,        halogen, NO₂, CN, C₁₋₆alkyl, CF₃, aryl, heteroaryl, cylcoalkyl,        cycloheteroalkyl, OCF₃, OR18, SR18, OC₂₋₆alkyl,        OC₂₋₆alkylNR18R19, Oaryl, Oheteroaryl, Ocycloalkyl,        Ocycloheteroalkyl, OC₁₋₆alkylaryl, OC₁₋₆alkylheteroaryl,        OC₁₋₆alkylcycloalkyl, OC₂₋₆cycloheteroalkyl, CO₂R18,        C₁₋₆alkylCO₂R18, CONR18R19, C₂₋₆alkylCONR18R19, NR18R19,        C₁₋₆alkylNR18R19, NR20C₁₋₆alkylNR18R19,        C₂₋₆allylNR20C₁₋₆alkylNR18R19, NR18COR19, C₁₋₆alkylNR18COR19,        C₁₋₆alkylINTR20CONR18R19, NR20CONR18R19, C₁₋₆alkylNR18SO₂R19,        NR18SO₂R19;        -   R18, R19 are each independently selected from H, C₁₋₄ alkyl,            C₁₋₄ alkyl cycloheteroalkyl, aryl, heteroaryl, C₁₋₄alkyl            aryl, C₁₋₄ alkyl heteroaryl, or may be joined to form an            optionally substituted 3-8 membered ring optionally            containing an atom selected from O, S, NR21;            -   R20, R21 are each independently selected from H,                C₁₋₄alkyl;                R6 is selected from H, C₁₋₄alkyl;                R7 is selected from H, C₁₋₄alkyl, SH, CN;                R8 is selected from OR9, NR9R10;    -   R9, R10 are each independently selected from H, C₂₋₄alkyl,        C₂₋₄alkylCO₂H, C₁₋₄ alkyl cycloheteroalkyl, aryl, heteroaryl,        C₁₋₄alkyl aryl, C₁₋₄ alkyl heteroaryl, or may be joined to form        an optionally substituted 3-8 membered ring optionally        containing an atom selected from O, S, NR11;        -   R11 is selected from H, C₁₋₄alkyl.

In a second aspect, the present invention provides a compound capable ofbinding to a Fc receptor and modulating Fc receptor activity having thegeneral formula II:

-   -   wherein    -   R1, R2, R3, R4, R5, R6, R7, R8, R9, and R10 are each        independently selected from H, halogen, NO₂, CN, C₁₋₆alkyl, CF₃,        aryl, heteroaryl, cylcoalkyl, cycloheteroalkyl, OCF₃, OR18,        SR18, OC₂₋₆alkylNR18R19, Oaryl, Oheteroaryl, Ocycloalkyl,        Ocycloheteroalkyl, OC₁₋₆alkylaryl, OC₁₋₆alkylheteroaryl,        OC₁₋₆alkylcycloalkyl, OC₁₋₆cycloheteroalkyl, CO₂R18,        C₁₋₆alkylCO₂R18, CONR18R19, C₁₋₆alkylCONR18R19, NR18R19,        C₂₋₆alkylNR18R19, NR20C₁₋₆alkylNR18R19,        C₁₋₆alkylNR20C₂₋₆alkylNR18R19, NR18COR19, C₁₋₆alkylNR18COR19,        C₂₋₆alkylNR20CONR18R19, NR20CONR18R19, C₁₋₆alkylNR18SO₂R19,        NR18SO₂R19;        -   R18, R19 are each independently selected from H, C″ alkyl,            C₁₋₄ alkyl cycloheteroalkyl, aryl, heteroaryl, C₁₋₄alkyl            aryl, C₁₋₄ alkyl heteroaryl, or may be joined to form an            optionally substituted 3-8 membered ring optionally            containing an atom selected from O, S, NR21;            -   R20, R21 are each independently selected from H,                C₂₋₄alkyl;    -   R11, R12 are each independently selected from H, C₁₋₄alkyl,        halogen, OC₁₋₄alkyl.

In a third aspect the present invention provides a compound capable ofbinding to a Fc receptor and modulating Fc receptor activity having thegeneral formula III:

-   -   wherein    -   R1, R2, R3, R4, R5 and R6 are each independently selected from        H, halogen, NO₂, CN, C₁₋₆alkyl, CF₃, aryl, heteroaryl,        cylcoalkyl, cycloheteroalkyl, OCF₃, OR18, SR18, OC₁₋₆alkyl,        OC₂₋₆alkylNR18R19, Oaryl, Oheteroaryl, Ocycloallyl,        Ocycloheteroalkyl, OC₁₋₆alkylaryl, OC₂₋₆alkylheteroaryl,        OC₁₋₆alkylcycloalkyl, OC₁₋₆cycloheteroalkyl, CO₂R18,        C₁₋₆alkylCO₂R18, CONR18R19, C₁₋₆alkylCONR18R19, NR18R19,        C₂₋₆alkylNR18R19, NR20C₁₋₆alkylNR18R19,        C₁₋₆alkylNR20C₁₋₆alkylNR18R19, NR18COR19, C₁₋₆alkylNR18COR19,        C₁₋₆alkylNR20CONR18R19, NR20CONR18R19, C₁₋₆alkylNR18SO₂R19,        NR18SO₂R19;        -   R18, R19 are each independently selected from H, C₁₋₄ alkyl,            C₁₋₄ alkyl cycloheteroalkyl, aryl, heteroaryl, C₁₋₄alkyl            aryl, C₁₋₄ alkyl heteroaryl, or may be joined to form an            optionally substituted 3-8 membered ring optionally            containing an atom selected from O, S, NR21;            -   R20, R21 are each independently selected from H,                C₁₋₄alkyl;    -   R7 is selected from H, C₁₋₆alkyl, CF₃, aryl, heteroaryl,        cylcoalkyl, cycloheteroalkyl, CO₂R18, C₁₋₆alkylCO₂R18,        CONR18R19, C₁₋₄alkylCONR18R19, NR18R19, C₁₋₆alkylNR18R19,        NR20C₁₋₄alkylNR18R19, C₁₋₄alkylNR20C₁₋₄alkylNR18R19, NR18COR19,        C₁₋₆alkylNR18COR19, C₂₋₆alkylNR20CONR18R19, NR20CONR18R19,        C₂₋₆alkylNR18SO₂R19, NR18SO₂R19.

In a fourth aspect the present invention provides a compound capable ofbinding to a Fc receptor and modulating Fc receptor activity having thegeneral formula IV:

-   -   wherein    -   R1, R2, R3, R4, R5 and R6 are each independently selected from        1-1, halogen, NO₂, CN, CF₃, aryl, heteroaryl, cylcoalkyl,        cycloheteroalkyl, OCF₃, OR18, SR18, OC₁₋₄alkyl,        OC₂₋₆alkylNR18R19, Oaryl, Oheteroaryl, Ocycloalkyl,        Ocycloheteroalkyl, OC₁₋₆alkylheteroaryl, OC₁₋₆alkylcycloalkyl,        OC₃₋₆cycloheteroalkyl, CO₂R18, C₁₋₄alkylCO₂R18, CONR18R19,        C₁₋₆alkylCONR18R19, NR18R19, C₁₋₄alkylNR18R19,        NR20C₁₋₆alkylNR18R19, C₁₋₆alkylNR20C₁₋₆alkylNR18R19, NR18COR19,        C₁₋₆alkylNR18COR19, C₁₋₆alkylNR20CONR18R19, NR20CONR18R19,        C₁₋₆alkylNR18SO₂R19, NR18SO₂R19;        -   R18, R19 are each independently selected from H, C₁₋₄ alkyl,            C₁₋₄ alkyl cycloheteroalkyl, aryl, heteroaryl, C₁₋₄alkyl            aryl, C₁₋₄ alkyl heteroaryl, or may be joined to form an            optionally substituted 3-8 membered ring optionally            containing an atom selected from O, S, NR21;            -   R20, R21 are each independently selected from H,                C₁₋₄alkyl.

In a fifth aspect, the present invention provides a compound capable ofbinding to a Fc receptor and modulating Fc receptor activity comprisinga core lipophilic group in the form of an Aryl ring substituted with agroup rich in π-electrons.

In a sixth aspect, the present invention provides a pharmaceuticalcomposition suitable for modulating Fc receptor activity in an animalcomprising one or more compounds according to the first to fifth aspectsof the present invention together with a pharmaceutically acceptablediluent.

In a seventh aspect, the present invention provides a method fortreating an autoimmune disease involving Fc receptor activity comprisingadministering to a subject in need of treatment with a pharmaceuticalcomposition according to the sixth aspect of the present invention.

In an eighth aspect, the present invention provides a method forobtaining a compound which modulates Fc receptor activity, the methodcomprising:

-   (a) providing or designing compounds having structural    characteristics to fit in the groove of the FcγRIIa structure; and-   (b) screening the compounds for modulating activity on the Fc    receptor.

In a ninth aspect, the present invention provides a compound whichmodulates Fc receptor activity obtained by the method according to theeighth aspect of the present invention.

In a tenth aspect, the present invention provides a method for treatingan autoimmune disease involving Fc receptor activity comprisingadministering to a subject in need of treatment with a pharmaceuticalcomposition containing a compound which modulates Fc receptor activityaccording to the ninth aspect of the present invention.

In an eleventh aspect, the present invention provides use of compositionaccording to the sixth aspect of the present invention in treatment ortherapies for autoimmune diseases involving Fc receptor activity.

In a twelfth aspect, the present invention provides use of a compoundaccording to the first to fifth aspects in the manufacture of amedicament for the treatment of an autoimmune disease.

DETAILED DESCRIPTION OF THE INVENTION

It has now been found that a new group or class of compounds haveactivity as Fc receptor modulating compounds and may be used inpharmaceutical compositions. These compounds typically have a coreLipophilic group, substituted with a group rich in π-electrons,preferably having a delocalised π-electron system. The compoundstypically include at least one acidic group having a π-electron system.

In a first aspect, the present invention provides a compound capable ofbinding to a Fc receptor and modulating Fc receptor activity having thegeneral formula I:

R1, R2, R3, R4, R5, are each independently selected from H, halogen,NO₂, CN, CF₃, aryl, heteroaryl, cylcoalkyl, cycloheteroalkyl, OCF₃,OR18, SR18, OC₁₋₆alkyl, OC₂₋₆alkylNR18R19, Oaryl, Oheteroaryl,Ocycloalkyl, Ocycloheteroalkyl, OC₁₋₆alkylaryl, OC₁₋₆alkylheteroaryl,OC₁₋₆alkylcycloalkyl, OC₁₋₆cycloheteroalkyl, CO₂R18, C₁₋₄alkylCO₂R18,CONR18R19, C₁₋₆alkylCONR18R19, NR18R19, C₁₋₆alkylNR18R19,NR20C₁₋₆alkylNR18R19, C₁₋₆alkylNR20C₁₋₆alkylNR18R19, NR18COR19,C₁₋₄alkylNR18COR19, C₁₋₆alkylNR20CONR18R19, NR20CONR18R19,C₁₋₄alkylNR18SO₂R19, NR18SO₂R19;

-   -   R18, R19 are each independently selected from H, C₁₋₄ alkyl,        C₁₋₄ alkyl cycloheteroalkyl, aryl, heteroaryl, C₁₋₄alkyl aryl,        C₁₋₄ alkyl heteroaryl, or may be joined to form an optionally        substituted 3-8 membered ring optionally containing an atom        selected from O, S, NR21;        -   R20, R21 are each independently selected from H, C₁₋₄alkyl;            R6 is selected from H,            R7 is selected from H, C₁₋₄alkyl, SH, CN;            R8 is selected from OR9, NR9R10    -   R9, R10 are each independently selected from H, C₁₋₄alkyl,        C₁₋₄alkylCO₂H, C₁₋₄ alkyl cycloheteroalkyl, aryl, heteroaryl,        C₁₋₄alkyl aryl, C₁₋₄ alkyl heteroaryl, or may be joined to form        an optionally substituted 3-8 membered ring optionally        containing an atom selected from O, S, NR11        -   R11 is selected from H, C₁₋₄alkyl.

In a preferred embodiment

R1, R2, R3, R4 and R5 are each independently selected from H, OH,OC₁₋₄alkyl, OC₁₋₄alkylaryl, C₂₋₄alkyl, halogen;R6 is selected from H, C₁₋₄allyl,R7 is selected from H, C₁₋₄alkyl, SH, CN;R8 is selected from OH, NR9R10;

-   -   R9, R10 are each independently selected from H, C₁₋₄alkyl,        C₁₋₄alkylCO₂H.

In a second aspect, the present invention provides a compound capable ofbinding to a Fc receptor and modulating Fc receptor activity having thegeneral formula II:

whereinR1, R2, R3, R4, R5, R6, R7, R8, R9, and R10 are each independentlyselected from H, halogen, NO₂, CN, C₁₋₆alkyl, CF₃, aryl, heteroaryl,cylcoalkyl, cycloheteroalkyl, OCF₃, OR18, SR18, OC₂₋₆alkylNR18R19,Oaryl, Ohetaryl, Ocycloalkyl, Ocyclohetalkyl, OC₁₋₆alkylaryl,OC₁₋₆alkylheteroaryl, OC₁₋₆alkylcycloalkyl, OC₁₋₆cycloheteroalkyl,CO₂R18, C₁₋₆alkylCO₂R18, CONR18R19, C₁₋₆alkylCONR18R19, NR18R19,C₁₋₆alkylNR18R19, NR20C₁₋₆alkylNR18R19, C₁₋₆alkylNR20C₁₋₆alkylNR18R19,NR18COR19, C₁₋₆alkylNR18COR19, C₁₋₆alkylNR20CONR18R19, NR20CONR18R19,C₁₋₆alkylNR18SO₂R19, NR18SO₂R19;

-   -   R18, R19 are each independently selected from H, C₁₋₄ alkyl,        C₁₋₄ alkyl cycloheteroalkyl, aryl, heteroaryl, C₁₋₄alkyl aryl,        C₁₋₄ alkyl heteroaryl, or may be joined to form an optionally        substituted 3-8 membered ring optionally containing an atom        selected from O, S, NR21;    -   R20, R21 are each independently selected from H, C₁₋₄alkyl;        R11, R12 are each independently selected from H, C₁₋₄alkyl,        halogen, OC₁₋₄alkyl.

In a preferred embodiment,

R1, R2, R3, R4, R5, R6, R7, R8, R10 are each independently selected fromH, C₁₋₄alkyl, OC₁₋₄alkyl, CO₂H, CN;R11, R12 are each independently selected from H, C₁₋₄alkyl.

In a third aspect the present invention provides a compound capable ofbinding to a Fc receptor and modulating Fc receptor activity having thegeneral formula III:

whereinR1, R2, R3, R4, R5 and R6 are each independently selected from H,halogen, NO₂, CN, C₁₋₆alkyl, CF₃, aryl, heteroaryl, cylcoalkyl,cycloheteroalkyl, OCF₃, OR18, SR18, OC₁₋₄alkyl, OC₂₋₆alkylNR18R19,Oaryl, Oheteroaryl, Ocycloalkyl, Ocycloheteroalkyl, OC₁₋₆alkylaryl,OC₁₋₆alkylheteroaryl, OC₁₋₆alkylcycloalkyl, OC₁₋₄cycloheteroalkyl,CO₂R18, C₁₋₆alkylCO₂R18, CONR18R19, C₁₋₆aklylCONR18R19, NR18R19,C₁₋₆alkylNR18R19, NR20C₁₋₆alkylNR18R19, C₁₋₆alkylNR20C₁₋₆alkylNR18R19,NR18COR19, C₁₋₆alkylNR18COR19, C₁₋₆alkylNR20CONR18R19, NR20CONR18R19,C₁₋₆alkylNR18CO₂R19, NR18SO₂R19;

-   -   R18, R19 are each independently selected from H, C₁₋₄ alkyl,        C₁₋₄ alkyl be joined to form an optionally substituted 3-8        membered ring optionally containing an atom selected from O, S,        NR21;    -   R20, R21 are each independently selected from H,        R7 is selected from H, C₁₋₆alkyl, CF₃, aryl, heteroaryl,        cylcoalkyl, cycloheteroalkyl, CO₂R18, C₁₋₄alkylCO₂R18,        CONR18R19, C₁₋₄alkylCONR18R19, NR18R19, C₁₋₆alkylNR18R19,        NR20C₁₋₄alkylNR18R19, C₁₋₆alkylNR20C₁₋₄alkylNR18R19, NR18COR19,        C₁₋₆allylNR18COR19, C₁₋₆alkylNR20CONR18R19, NR20CONR18R19,        C₁₋₆alkylNR18SO₂R19, NR18SO₂R19 wherein R18, R19 are as defined        above.

In a preferred embodiment

R1, R2, R3, R4, R5, and R6 are each independently selected from H,halogen, OH, OC₁₋₄alkyl, C₁₋₄alkyl;R7 is selected from H, C₂₋₄alkyl, C₁₋₄alkylCO₂H.

In a fourth aspect the present invention provides a compound capable ofbinding to a Fc receptor and modulating Fc receptor activity having thegeneral formula IV:

R1, R2, R3, R4, R5 and R6 are each independently selected from H,halogen, NO₂, CN, C₁₋₆alkyl, CF₃, aryl, heteroaryl, cylcoalkyl,cycloheteroalkyl, OCF₃, OR18, SR18, OC₁₋₆alkyl, OC₂₋₆alkylNR18R19,Oaryl; Oheteroaryl, Ocycloalkyl, Ocycloheteroalkyl, OC₁₋₆alkylaryl,OC₁₋₆alkylheteroaryl, OC₁₋₆alkylcycloalkyl, OC₁₋₆cycloheteroalkyl,CO₂R18, C₁₋₆alkylCO₂R18, CONR18R19, C₁₋₆alkylCONR18R19, NR18R19,C₁₋₆alkylNR18R19, NR20C₁₋₆alkylNR18R19, C₁₋₆alkylNR20C₁₋₆alkylNR18R19,NR18COR19, C₁₋₆alkylNR18COR19, C₁₋₆alkylNR20CONR18R19, NR20CONR18R19,C₁₋₆alkylNR18CO₂R19, NR18SO₂R19;

-   -   R18, R19 are each independently selected from H, C₁₋₄ alkyl,        C₁₋₄ alkyl cycloheteroalkyl, aryl, heteroaryl, C₁₋₄alkyl aryl,        C₁₋₄ alkyl heteroaryl, or may be joined to form an optionally        substituted 3-8 membered ring optionally containing an atom        selected from O, S, NR21;    -   R20, R21 are each independently selected from H, C₁₋₄alkyl.

In a preferred embodiment,

R1, R2, R3, R4 are each independently selected from H, halogen, NO₂,OC₁₋₄alkyl, C₁₋₄alkyl;R5 is selected from H, C₁, OC₁₋₄alkyl, OC₁₋₄alkylaryl, OC₁₋₄cycloalkyl;R6 is selected from CO₂H, CONR₇R₉;

-   -   R7, R8 are each independently selected from H, 5-tetrazole.

In the above description it will be appreciated that:

-   -   C₁₋₄ alkyl means an unsubstituted or optionally substituted        straight or branched alkyl chain.    -   Aryl means unsubstituted or optionally substituted phenyl or        naphthyl.    -   Heteroaryl means an unsubstituted or optionally substituted 5-        or 6-membered heteroaromatic ring containing one or more        heteroatoms selected from O, N, S.    -   Cycloalkyl means an optionally substituted 3-8 membered        saturated ring.    -   Cycloheteroalkyl means an optionally substituted 3-8 membered        saturated ring containing 1-3 heteroatoms selected from O, S,        NR24, where R24 is H, C₁₋₄ alkyl, aryl, heteroaryl.

In a fifth aspect, the present invention provides a compound capable ofbinding to a Fc receptor and modulating Fc receptor activity comprisinga core lipophilic group in the form of an Aryl ring substituted with agroup rich in π-electrons.

Preferably, the substituent on the Aryl ring comprises a 5 or 6 memberedring system having π bonds and/or a carbon chain comprising, orsubstituted with heteroatoms having π electrons. Preferably, thesubstituted Aryl ring is selected from:

and salts thereof, whereinR1 is selected from the group —COOH—, —COOCH₃, —CN, halides andhydrogen,R2 is selected from the group —NO₂, —COOH, halides and hydrogen;X is selected by the group —S(O)Ar(COOH), —S(CH₂)₃CN, —C(O)CH₂SAr(COOH),

—C(O)CH₂SCH₂C(O)Ar(COOH), —NHC(O)NHAr(COOH), —NHC(O)NH[CNC(COOH)NNH],—CH₂NCHAr(COOH), —CH₂SAr(COOH), —NHCH₂Ar(COOH), —NCHAr(COOH),—NCHAr(COOH), —(CH(O)CH)C(O)Ar(COOH), —(CH)₂C(O)(C₄H₄N), —CH₂C(SH)COOH,—CH₂OC(O)NH(CH₂)₂₋₅COOH, —CH₂OC(O)NH[CH₂C(O)NH]₂—CH₂COOH,—CH₂OC(O)NH[CH₂C(O)NH]₂—CH(CH₃)COOH, —CH₂OC(O)NH(CH₂)₃COOH,—CH₂NHC(O)NH(CH₂)₃₋₅COOH, —CH₂NHC(O)(CH₂)₂₋₃COOH,—CH₂CH₂O—Ar[(CH)CHC(O)OH], —NHC(O)NH(CH₂)₃₋₅COOH, —NHNCHAr(COOH) and the

ring systems —C(O)Ar(COOH)—, —S(O)C(COOH)C(Cl)—, —SC(COOH)C(Cl)—,

—SC(COOH)C(OC₆H₁₁)— and —SC[C(O)NH—(CN₄H)]C[OCH(CH₃)₂]—, and—C(O)Ar(COOH)(NO₂)—.

The aromatic compound may be, for example, a substituted Aryl ring (Ar)selected from:

or salts thereof, wherein

-   -   when X is chosen from the group —S(O)Ar(m-COOH) [032],        —S(CH₂)₃CN [239], —C(O)CH₂SAr(m-COOH) [217],        —C(O)CH₂SCH₂C(O)Ar(m-COOH) [292], —NHC(O)NHAr(m-COOH) [192],        —NHC(O)NH[CNC(COOH)NNH] [219], —CH₂NCHAr(m-COOH) [200],        —CH₂SAr(m-COOH) [255], —NHCH₂Ar(m-COOH) [100], —NCHAr(m-COOH)        [076], —NCHAr(p-COOH) [081] or —(CH(O)CH)C(O)Ar(m-COOH) [027],        R1 is —COOH, located at position 3 on the aryl ring and R2 is        hydrogen;    -   when X comprises a ring system —C(O)Ar(m-COOH)-[001], R1 is        —COOH located at position 3 on the aryl ring and R2 is hydrogen;    -   when X comprises a ring system —S(O)C(COOH)C(Cl)-[044] or        —SC(COOH)C(Cl)-[026], R1 is —NO₂ located at position 6 on the        aryl ring and R2 is hydrogen;    -   when X comprises a ring system —SC(COOH)C(OC₆H₁₁)— [276], R1 is        —OCH₃ located at position 5 on the aryl ring and R2 is hydrogen;    -   when X comprises a ring system        —SC[C(O)NH—(CN₄H)]C[OCH(CH₃)₂]-[090], R1 is —OCH₃ located at        position 7 on the aryl ring and R2 is hydrogen;    -   when X is the ring system —C(O)Ar(m-COOH)(m-NO₂)— [261], R1 and        R2 are —NO₂ located at positions 3 and 5 on the aryl ring;    -   when X is the fused heteroatomic fused ring system        —SC[C(O)NH(CN₄H)]C[OCH(CH₃)₂]-[092], R1 is —OCH₃ located at        position 5 on the aryl ring and R2 is —NO₂ located at position 4        on the aryl ring;    -   when X is —(CH)₂C(O)(C₄H₄N) [238], R1 is —COOH located at        position 2 on the aryl ring and R2 is hydrogen;    -   when X is —C(O)(CH)₂Ar [237], R1 is COOH located at position 4        on the aryl ring and R2 is hydrogen;    -   when X is —CH₂C(SH)COOH [297], R1 is —OH located at position 2        on the aryl ring and R2 is hydrogen;    -   when X is —C(O)CH₂S—Ar(m-COOH) [216] [294], R1 is —CN or H        located at position 3 on the aryl ring and R2 is hydrogen;    -   when X is chosen from the group comprising        —CH₂OC(O)NH(CH₂)₃₋₅COOH, [197, 233, 336, 355],        —CH₂OC(O)NH[CH₂C(O)NH]2-CH₂COOH [234],        —CH₂OC(O)NH[CH₂C(O)NH]₃CH(CH₃)COOH [235], —[CH₂OC(O)NH]₂CH₂COOH        [236], —CH₂NHC(O)NH(CH₂)₃₋₅COOH [337 to 339],        —CH₂NHC(O)(CH₂)₂₋₃COOH [343, 344], —CH₂O—Ar[(p-CH)CHC(O)OH [299]        and —CH₂NCHAr(m-COOH) [331] both R1 and R2 are hydrogen;    -   when X is chosen from the group —NHC(O)NH(CH₂)₃₋₅COOH [340, 341,        342] then R1 is —COOCH₃ located at position 3 on the aryl ring        and R2 is hydrogen;    -   when X is chosen from the group —NCHAr(m-COOH) [114] then R1 and        R2 are —COOH located at positions 3 and 5 on the aryl ring; and    -   when X is chosen from the group —NHNCHAr(m-COOH) [080] then R1        and R2 are —Cl located at positions 3 and 5 on the aryl ring.

Where used herein the numbers in square brackets correspond to thecompounds listed in Table 1.

The numbering used herein has been kept as close as possible to theIUPAC convention nomenclature. In particular when X is located at asingle position on the Aryl ring the numbering of the positions on thearyl ring is as follows:

For example, compounds [153], [032], [294], [297], [197], [216], [238],[237] [152], [239], [217], [299], [292] and [113] follow this numberingscheme.

When X is a fused heteroatomic ring system (where Y is nitrogen orsulphur), the numbering on the aryl ring is as follows:

For example, compounds [044], [026], [276], [090] and [092] follow thisnumbering scheme.

In a preferred embodiment, the compound is selected from compounds[197], [216], [217], [238], [239], [261], [294], [297] and [299]. Morepreferably the compound is selected from and [294].

In a sixth aspect, the present invention provides a pharmaceuticalcomposition suitable for modulating Fc receptor activity in an animalcomprising one or more compounds according to the first to fifth aspectsof the present invention together with a pharmaceutically acceptablediluent.

In a seventh aspect, the present invention provides a method fortreating an autoimmune disease involving Fc receptor activity comprisingadministering to a subject in need of treatment with a pharmaceuticalcomposition according to the sixth aspect of the present invention.

In an eighth aspect, the present invention provides a method forobtaining a compound which modulates Fc receptor activity, the methodcomprising:

-   (a) providing or designing compounds having structural    characteristics to fit in the groove of the FcγRIIa structure; and-   (b) screening the compounds for modulating activity on the Fc    receptor.

In a preferred form, step (a) comprises functionalising the compoundswith one or more substituent groups.

Preferably, the compounds are screened by a FcγRIIa dependent plateletactivation assay and/or aggregation assay where platelets are activatedusing heat aggregated human immunoglobulin G as an immune complex. Thecompounds can be tested in a collagen-arthritis model in FcγRIIatransgenic animals. Such a model is disclosed, for example, inPCT/AU03/00718 entitled “Transgenic Animal Model for Autoimmune Disease”in the name of Arthron Ltd.

If desired the compounds may be screened by measuring the inhibition ofan Fc receptor to a ligand in an ELISA based system. For example, if thereceptor is Fey receptor, the ligand used may be selected from heataggregated IgG (HAGG) or monomeric IgG or the like.

In a ninth aspect, the present invention provides a compound whichmodulates Fc receptor activity obtained by the method according to theeighth aspect of the present invention.

In a tenth aspect, the present invention provides a method for treatingan autoimmune disease involving Fc receptor activity comprisingadministering to a subject in need of treatment with a pharmaceuticalcomposition containing a compound which modulates Fc receptor activityaccording to the ninth aspect of the present invention.

In an eleventh aspect, the present invention provides use of compositionaccording to the sixth aspect of the present invention in treatment ortherapies for autoimmune diseases involving Fc receptor activity.

In a twelfth aspect, the present invention provides use of a compoundaccording to the first to fifth aspects in the manufacture of amedicament for the treatment of an autoimmune disease.

Typically, the autoimmune disease involves aggregates of antibodies areproduced or where immune complexes are produced by contact of antibodywith intrinsic or extrinsic antigen causing damage to normal tissue ofan individual.

In a particularly preferred embodiment of the present invention,modulation of Fc receptors by the above identified compounds is used totreat a disease where aggregates of antibodies are produced or whereimmune complexes are produced by contact of antibody with intrinsic orextrinsic antigen. Modulation of Fc receptors by the above identifiedcompounds can also be used to reduce IgG-mediated tissue damage, toreduce IgE-mediated response and/or to reduce inflammation in a patient.

The present invention provides a variety of compounds which can modulatethe interaction between Fc receptors and immunoglobulins. Withoutwishing to be bound by theory it is believed that these compoundsinterfere with the groove, or dimerization interface between two FcγRIIproteins, thereby affecting cellular signal transduction through one orboth of the FcR proteins. Specifically, it is believed that peptideresidues 117-131 and 150-164 of FcγRII make up the interfacial area ofthe FcγRIIa dimer, and the compounds of the present invention may mimicor bind to these regions and thus have activity as good bindingmodulators.

Specifically, and again without wishing to be bound by theory, it isbelieved that the compounds of the present invention can provide strongπ-π interaction and/or hydrogen-bonding with the wall of the groovewhile the hydrogen bonding and/or acidic groups interact with the aminoacid residues at the lip and floor of the groove.

Compounds of the invention may also bind to other regions of thereceptor, as indicated by computer modelling or “docking”. For example,some compounds may bind to the FG loop of the Fcγ receptor, or to areasaround tryptophan residues such as Trp90 or Trp 113.

It is to be understood that the scope of this invention includes isomersof the relevant compounds and mixtures thereof. Furthermore compounds ofthe present invention having chiral centres may be synthesisedenantioselectively or a mixture of enantiomers and/or diastereomers canbe prepared and separated. The resolution of the diasteromers may becarried out by any procedure known in the art. When the compounds of thepresent invention contain an olefin moiety which can be either of cis-or trans-configuration, the compounds can be synthesized to produce cis-or trans-olefin selectively as the predominant product. Alternativelythe compounds containing an olefin moiety can be produced as a mixtureof cis- and trans-olefins and separated using known procedures.

The compounds of the present invention may form salts with acids when abasic functional group is present and salts with bases when an acidfunctional group is present. All such salts are useful in the isolationand/or purification of the new compounds. Of particular value are thepharmaceutically acceptable salts with both acids and bases. Suitableacids include, for example hydrochloric, oxalic, sulphuric, nitric,benzenesulphonic, toluenesulphonic, acetic, maleic, tartaric and thelike which are pharmaceutically acceptable. Basic salts forpharmaceutical use include sodium, potassium, calcium and magnesiumsalts.

Selection

The compounds of the present invention are preferably selected accordingto the following protocol:

-   (a) Potentially suitable compounds are designed on the basis of    their structural characteristics and likely fit in the groove of the    FcγRIIa structure; part of the design process is to modify the    compounds by functionalising them with one or more substituent    groups;-   (b) The compounds identified at (a) are subjected to an in vitro    screening program to identify those with the best activity:

(i) Evaluation of Inhibitory Activity in vitro

-   -   The compounds of Table 1 were screened in a FcγRIIa dependent        platelet activation assay and/or aggregation assay where        platelets are activated using heat aggregated human        immunoglobulin G as an immune complex. Compounds inhibiting this        process were then tested for specificity. Note that the        platelets were used as the target as the only Fc receptor        expressed on these cells is FcγRIIa. In addition, they are very        difficult to inhibit and therefore this assists in identifying        compounds with reasonable potency.    -   The compounds may also be screened using an ELISA inhibition        assay to detect the blockade of IgG interaction with FcγRIIa.

(ii) Evaluation of Specificity of Inhibitors in vitro

-   -   The compounds were tested for activity against other platelet        activation pathways. These were principally induced by        arachidonic acid and/or ADP—some of these compounds have also        been tested for their capacity to inhibit collagen and/or        thrombin induced platelet activation.

(iii) Evaluation of in vitro Potency

-   -   The specific inhibitory compounds were then titrated in the        platelet activation assay.

(iv) Evaluation of in vivo Potency

-   -   Compounds showing best activity were tested in the        collagen-arthritis model in FcγRIIa transgenic animals.

Table 2 depicts the compounds that displayed the most promisingactivities.

Preferably the compounds of the present invention modulate Fc receptorsselected from the group consisting of FcαR, FcεR, FcγR, and mixturesthereof, more preferably from the group consisting of FcγRIIa, FcγRIIb,FcγRIIIb, FcγRIIc and mixtures thereof and most preferably the FcγRIIareceptor. The compounds of the present invention can be used in avariety of applications including treatment or diagnosis of any diseasewhere aggregates of antibodies are produced and where immune complexesare produced by contact of antibody with intrinsic or extrinsic antigen.Exemplary treatments and diagnosis applicable by the compounds of thepresent invention include immune complex diseases; autoimmune diseasesincluding but not limited to rheumatoid arthritis, systemic lupuserythematosus, immune thrombocytopenia, neutropenia, hemolytic anaemias;vasculities including but not limited to polyartheritis nodosa, systemicvasculitis; xenograft rejection; and infectious diseases where FcRuptake of virus enhances infection including but not limited toflavivirus infections such as Dengue virus-dengue hemorrhagic fever andmeasles virus infection. The compounds of the present invention can alsobe used to reduce IgG mediated tissue damage and to reduce inflammation.

The compounds of the present invention can also enhance leukocytefunction by enhancing FcR function. These functions include antibodydependent cell mediated cytotoxicity, phagocytosis, release ofinflammatory cytokines. Exemplary treatments and diagnosis for enhancedFcR function include any infection where normal antibodies are producedto remove the pathogen; and any disease requiring FcR function wherenatural or recombinant antibodies can be used in treatment such ascancer and infections, for example the antibody can be administered incombination with the compound of the present invention to enhance theeffect of the antibody treatment.

The compounds of the present invention can be administered to a patientto achieve a desired physiological effect. Preferably the patient is ananimal, more preferably a mammal, and most preferably a human. Thecompound can be administered in a variety of forms adapted to the chosenroute of administration, that is, orally or parenterally. Parenteraladministration includes administration by the following routes:intravenous; intramuscular; subcutaneous; intraocular; intrasynovial;transepithelially including transdermal, ophthalmic, sublingual andbuccal; topically including opthalmic, dermal, ocular, rectal and nasalinhalation via insufflation and aerosol; intraperitoneal; and rectalsystemic.

The active compound can be orally administered, for example, with aninert diluent or with an assimilable edible carrier, or it can beenclosed in hard or soft shell gelatin capsules, or it can be compressedinto tablets, or it can be incorporated directly with the food of thediet. For oral therapeutic administration, the active compound may beincorporated with excipient and used in the form of ingestible tablets,buccal tablets, troches, capsules, elixers, suspensions, syrups, wafers,and the like.

Such compositions and preparations can contain any therapeuticallyeffective amount of active compound.

The tablets, troches, pills, capsules and the like can also contain thefollowing: a binder such as gum tragacanth, acacia, corn starch orgelatine; excipients such as dicalcium phosphate; a disintegrating agentsuch as corn starch, potato starch, alginic acid and the like; alubricant such as magnesium stearate; and a sweetening agent such assucrose, lactose or saccharin can be added or a flavouring agent such aspeppermint, oil of wintergreen, or cherry flavouring. When the dosageunit form is a capsule, it can contain, in addition to materials of theabove type, a liquid carrier. Various other materials can be present ascoatings or to otherwise modify the physical form of the dosage unit.For instance, tablets, pills or capsules can be coated with shellac,sugar or both. A syrup or elixir can contain the active compound,sucrose as a sweetening agent, methyl and propylparabens aspreservatives, a dye and flavouring such as cherry or orange flavour. Ofcourse, any material used in preparing any dosage unit form should bepharmaceutically pur and substantially non-toxic in the amountsemployed. In addition, the active compound can be incorporated intosustained-release preparations and formulations.

The active compound can also be administered parenterally. Solutions ofthe active compound as a free base or pharmacologically acceptable saltcan be prepared in water suitably mixed with a surfactant such ashydroxypropylcellulose. dispersions can also be prepared in glycerol,liquid polyethylene glycols, and mixtures thereof and in oils. Underordinary conditions of storage and use, these preparations contain apreservative to prevent the growth of microorganisms.

The pharmaceutical forms suitable for injectable use include sterileaqueous solutions or dispersions and sterile powders for theextemporaneous preparation of sterile injectable solutions ordispersions. In all cases the form must be sterile and must be fluid tothe extent that easy syringability exists. It can be stable under theconditions of manufacture and storage and must be preserved against thecontaminating action of microorganisms such as bacteria and fungi. Thecarrier can be a solvent of dispersion medium containing, for example,water, ethanol, polyol (e.g. glycerol, propylene glycol, and liquidpolyethylene glycol, and the like), suitable mixtures thereof, andvegetable oils. The proper fluidity can be maintained, for example, bythe use of surfactants. The prevention of the action of microorganismscan be brought bout by various antibacterial and antifungal agents, forexample, parabens, chlorbutanol, phenol, sorbic acid, thimerosal and thelike. In many cases it will be preferable to include isotonic agentssuch as sugars or sodium chloride. Prolonged absorption of theinjectable compositions of agents delaying absorption such as aluminiummonostearate and gelatin.

Sterile injectable solutions are prepared by incorporating the activecompound in the require amount in the appropriate solvent with variousother ingredients as required, followed by filtered sterilisation.Generally, dispersions are prepared by incorporating the varioussterilised active ingredients into a sterile vehicle which contains thebasic dispersion medium and the required other ingredients. In the caseof sterile powders for the preparation of sterile injectable solutions,the preferred drying technique which yield a powder of the activeingredient plus any additional desired ingredient from previouslysterile-filtered solution thereof.

The therapeutic compounds of the present invention can be administeredto a mammal alone or in combination with pharmaceutically acceptablecarriers, as noted above, the proportion of which is determined by thesolubility and chemical nature of the compound, chosen route ofadministration and standard pharmaceutical practice. The compounds mayalso be co-administered with other agents such as methotrexate, Enbrel,Ramicade, Kinaret or the like.

Additional aspects, advantages, and novel features of this inventionwill become apparent to those skilled in the art upon examination of thefollowing non-limiting examples and the Figures in which:

FIG. 1( a) is a graph of % Inhibition (p-selectin loss) against dosagelevel, illustrating inhibition of IgG induced platelet activation as afunction of dose responses using FACS;

FIG. 1( b) is a graph depicting inhibition of Platelet Aggregation bycompound as a function of time (in minutes);

FIG. 2( a) is a graph of Arthritis Index as a function of time (in days)for treatment of FcγRIIa transgenic mice with compound [153] using fourdifferent dosage regimes, as compared with phosphate buffered saline(PBS);

FIGS. 2( b) to (d) which depict the individual dosage regimes of FIG. 2(a) with error bars, as compared with PBS;

FIG. 3 is a graph of Arthritis Index against time in Days for treatmentof control mice (non-transgenic mice) with compound [153] as comparedwith PBS;

FIG. 4 is a graph of % Inhibition of IgG induced platelet activationagainst compound Concentration (mM) for some of the compounds of thepresent invention;

FIG. 5 is a graph of % Inhibition of Platelet Activation againstcompound Concentration (mM) for further compounds of the presentinvention; and

FIG. 6 is a graph of % Inhibition of Platelet Activation againstcompound Concentration (mM) for compounds VIB 238, 239 and 197 of thepresent invention.

EXAMPLE

The compounds of the present invention were selected on the basis oftheir in vitro and in vivo activity as follows;

(i) In vitro Assays

The compounds of the present invention were initially screened in arapid FACS screening assay, measuring activation of human platelets byheat aggregated IgG. Platelets have only one type of Fcγ receptor,FcγRIIa, hence the use of human platelets eliminated the confoundingeffects of other Fcγ receptors. In addition, platelets are verysensitive to a range of stimuli and activate rapidly. Activation ismeasured by the appearance of the protein P-Selectin on the plateletmembrane after exposure to various stimuli. The stimuli were heataggregated with IgG and as specificity controls, collagen or thrombin.

Specifically, this assay utilises washed platelets and heat aggregatedIgG (HAGG) as an immune complex (agonist) to activate and crosslinkFcγRIIa. Because this is a primary screen a single concentration ofsmall molecule inhibitor is added to the platelets (final concentrationof 500 μg/ml) and allowed to incubate for 30 minutes. Heat AggregatedIgG (HAGG) (40 μg/ml) is then added to the platelets and allowed toincubate for 30 minutes. Paraformaldehyde is added to the platelets for30 minutes prior to washing. Anti-P-Selectin (FITC conjugated) andAnti-CD41 (PE conjugated) are added and the platelets are then screenedby FACS to detect expression of P-Selectin, a marker of plateletactivation and CD41, which is expressed by all viable platelets. Thedose response results generated using FACS for compounds [153] and [154]are depicted in FIG. 1( a).

Compounds that inhibited platelet activation were then screened using asecond, more comprehensive platelet aggregation assay. This assay wasused to confirm that the drug compounds cannot only prevent activationbut also the aggregation that follows such activation. The aggregationprocess is extremely difficult to inhibit and is one of the most potentbiological cell activation systems known. Compounds that are able toinhibit this process were preferred candidates for in vivo studies(described below).

The specificity of the compounds of the present invention was confirmedby testing for inhibition of other platelet stimuli including thrombin,ADP, arachidonic acid and collagen. The specificity assay compares theeffects of the small molecule inhibitors on HAGG (FcγRIIa) activationand the unrelated activation by arachidonic acid, ADP and/or thrombinwhich are potent stimulators of platelets. This assay also indicatesthat the small molecule inhibitor has not killed the platelets.

400 μl of washed platelets are incubated in the presence of a range ofconcentrations of small molecule inhibitor. The agonist, eg HAGG (200μg/ml) is then added and aggregation measured in an aggregometer, asdescribed by others (Ozaki, Y.; 1998, Sysmex Journal International 8:15;Gratacap M. P. et al; Blood 96:3439 and Gross B. S. et al (1999) Blocid94:4166).

The compounds selected to proceed to in vitro testing had to havespecificity for FcγRIIa based on these assays and those that inhibitother mechanisms of platelet activation did not proceed to in vitrotesting. The performance of compound [153] in this assay is depicted inFIG. 1( b) which shows the functionality of the platelets in response tostimulus by arachidonic acid after drug treatment.

In summary, for each compound tested the activity was measured as afunction of inhibition of platelet activation and/or plateletaggregation as detailed above. Specificity is defined as specificinhibition of immune complex induced platelet activation but with noeffect on arachidonic acid induced activation (and where tested noeffect on thrombin, collagen or ADP induced activation).

Compounds were also screened using an ELISA Inhibition Assay. HumanSerum Albumin genetically fused to FcγRIIa (HSA-FcγRIIa) was bound to anELISA plate at a concentration of 5 μg/ml. The small molecule inhibitorswere titrated from a starting concentration of 5 mg/ml and allowed toincubate in the presence of the receptor. A human IgG complex (0.2μg/ml) is then added to the plate and the extent of inhibition of IgGbinding by the small molecule inhibitors was measured using HRP labelledanti-human antibody.

Other cell based assays may also be used in addition to the above. Forexample, assays that measure events dependent on Fc receptor modulationsuch as Ca²⁺ mobilisation or cytokine production may be used.

(ii) In vivo Testing

Genetically engineered mice were used to test the interaction of thecompounds of the present invention with the human form of the FcγRIIaprior to clinical studies. The mice used have the human form of FcγRIIagenetically inserted into their DNA so that the mice produce humanreceptors on the surface of their inflammatory white blood cells andplatelets. Specifically the mice used were C57BL/6/SJL, H-2b inbred miceexpressing the FcγRIIa transgene on platelets, neutrophils andmacrophages at physiological levels. The severity of arthritis in micewas considerably greater in the FcγRIIa transgenic mice than in normalcontrol mice that do not express the receptor.

Collagen-induced arthritis was chosen as a suitable model for testingthe in vivo activity of a selection of compounds of the presentinvention. Mice were immunised with collagen, and boosted 21 days laterat which time they were given the first dose of one of the compounds.The induction of arthritis using collagen was carried out according tothe well described methods (Campbell, Bendele et al, 1997, Ann. Rheum.Dis. 56(6): 364-8). An emulsion is formed by combining 2 mg/ml chickencollagen type II dissolved in 10 mM acetic add in an equal volume ofComplete Freund's Adjuvant. One hundred microlitres of the emulsion wasinjected intradermally at the base of the tail. The same dose wasprepared and administered proximal to the primary site 21 days later.

Four dosing regimes were tested, each commencing 21 days after theabove-mentioned immunisation with collagen:

-   -   Regime 1: single dose of 7.5 my every third day for four doses,    -   Regime 2: single initial dose of 7.5 mg followed by daily doses        of 1 mg per day for 14 days,    -   Regime 3: single dose of 1.0 mg per day for 14 days, and    -   Regime 4: single dose of 0.3 mg per day for 14 days.

As a control, untreated transgenic mice were examined 23 to 25 daysafter immunisation with collagen.

A standard arthritis scoring system index was used to measure theseverity of the disease for the duration of the treatment period (up to60 days). The mice were examined 3 times per week from day 14 to 36after the first collagen injection. The severity of arthritis was ratedon a scale from 0 to 3 for each limb based on the swelling, redness andjoint function. The score (arthritis index) for each mouse wascalculated as the sum of the score from the four limbs according to thefollowing:

-   -   Score 0=normal    -   Score 1=mild swelling/redness    -   Score 2=severe swelling and redness    -   Score 3=severe swelling and redness accompanied by joint        dysfunction.

Dose response studies were undertaken to determine the minimum effectivedose of compound [153] that can effectively inhibit development ofcollagen induced arthritis. FIG. 2( a) is a graph of Arthritis Indexagainst time (in days) for treatment of FcγRIIa transgenic mice withcompound [153] as compared with treatment with PBS. The mice were testedbetween 12 to 14 weeks of age with compound [153] according toabovementioned dosage Regimes 1 to 4. By comparison with the PBS dosingregime, all is the dosage regimes were successful, Regime 1 beingcomparatively more effective than Regimes 1, 2 or 3. FIGS. 2( b) to 2(e)depict each of the individual dosage regimes depicted in FIG. 2( a) withthe addition of error bars.

FIG. 3 is a graph of Arthritis Index against time in Days for treatmentof control (non-transgenic) mice with compound [153]. The mice weretested between 12 to 14 weeks of age with compound [153] according toabovementioned dosage Regimes 3 and 4. As can be seen from the graph,the compound does not have a significant effect in non-transgenic miceimplying specificity of action. Mice that have been treated in this waydo not develop more severe arthritis upon cessation of treatment.

FIG. 4 is a graph of % Inhibition of IgG induced platelet activationagainst compound Concentration (mM) for nine of the compounds of thepresent invention, namely [216], [217], [261], [292], [294], [297],[299], [153] and [197]. The compounds were titrated and evaluated forcapacity to prevent aggregated IgG induction of p-selectin expression asa measure of activation.

FIG. 5 is a graph of % Inhibition of Platelet Activation againstcompound Concentration (mM) for three of the compounds of the presentinvention, namely [113], [152] and [153].

FIG. 6 is a graph of % Inhibition of Platelet Activation againstcompound Concentration (mM) for four of the compounds of the presentinvention, namely [238], [239], [197] and [153].

FIGS. 4 to 6 showing the in vitro dose responses are, for the most part,only those compounds that have been through the entire selection programto the point where they would be ready for testing in vivo.

Preparative Examples

The present invention will be further illustrated with reference to thefollowing examples of preparation of compounds according to theinvention:

Preparation of3-Isopropoxy-7-methoxy-N-(1H-1,2,3,4-tetrazol-5-yl)-1-benzo[b]thiophene-2-carboxamide(VIB 090) (a) 3-Chloro-5-methoxy-1-benzo[b]thiophene-2-carbonyl chlorideand 3-chloro-7-methoxy-1-benzo[b]thiophene-2-carboxylate

3-Methoxy cinnamic acid (5.0 mg, 28.06 mmol) was dissolved in anhydrousDMF (2.15 mL), chlorobenzene (40.0 mL) and pyridine (230.0 mL). To thissolution was added thionyl chloride (10.5 mL) in a dropwise fashion atroom temperature. The reaction mixture was heated to reflux for 24hours. The reaction mixture was allowed to cool to room temperature andthe solvents were evaporated under reduced pressure. Attempts torecrystallise the residue from t-BuOCH₃ and THF/hexane wereunsuccessful. The residue was taken up in THF, filtered and evaporatedunder reduced pressure to afford a yellow solid, which was used withoutfurther purification in the next step.

(b) Isopropyl 3-isopropoxy-7-methoxy-1-benzo[b]thiophene-2-carboxylate

The crude mixture of 3-chloro-5-methoxy-1-benzo[b]thiophene-2-carbonylchloride and 3-chloro-7-methoxy-1-benzo[b]thiophene-2-carbonyl chloride(7.32 g, 28.06 mmol) was dissolved in THF (30.0 mL) and isopropanol(30.0 mL) and the reaction mixture was heated to reflux for 5 hours. Thereaction mixture was then allowed to cool to room temperature, thenconcentrated under reduced pressure. T.L.C. (dichloromethane/hexane)(3/7) indicated 2 components, which were separated using columnchromatography eluting with (dichloromethane/hexane (3/7) to afford(483.0 mg, 6.0%) of the desired isopropyl3-isopropoxy-7-methoxy-1-benzo[b]thiophene-2-carboxylate as a whitepowder, which was further purified by recrystallisation from hexane and(1.39 g, 17.0%) of isopropyl3-isopropoxy-5-methoxy-1-benzo[b]thiophene-2-carboxylate.

(c) Isopropyl 3-isopropoxy-7-methoxy-1-benzo[b]thiophene-2-carboxylate

Isopropanol (2.0 mL) was added to a suspension of sodium hydride (60%dispersion, 110.0 mg, 2.75 mmol) and the reaction mixture was stirred atroom temperature for 90 minutes. Isopropyl3-chloro-7-methoxy-1-benzo[b]thiophene-2-carboxylate (400.0 mg, 1.4mmol) was dissolved in anhydrous THF (2.0 mL) and the solution was addedto the sodium hydride suspension and the resulting reaction mixture washeated to reflux for 17 hours. The reaction mixture was allowed to cooland the reaction mixture was concentrated under reduced pressure. Theresulting residue was partitioned between hexane and water. The aqueousphase was extracted with hexane and the combined hexane extracts weredried, filtered and evaporated under reduced pressure to afford (433.0mg, 99.9%) of the desired isopropyl3-isopropoxy-7-methoxy-1-benzo[b]thiophene-2-carboxylate as a viscousyellow oil. M.S. m/z 308 (M)⁺.

(d) 3-Isopropoxy-7-methoxy-1-benzo[b]thiophene-2-carboxylic acid

Isopropyl 3-isopropoxy-7-methoxy-1-benzo[b]thiophene-2-carboxylate(433.3 mg, 1.4 mmol) was dissolved in methanol (3.0 mL) and aqueous 1Nsodium hydroxide solution (7.0 mL) was added and the reaction mixturewas heated to reflux for 7 hours. The reaction mixture was allowed tocool then poured into water (30.0 mL) and the aqueous reaction mixturewas acidified with concentrated hydrochloric acid and extracted withdichloromethane. The dichloromethane phase was dried, filtered andevaporated under reduced pressure to afford an off-white residue, whichwas recrystallised from methanol/water to afford (99.9 mg, 36.1%) of thedesired 3-isopropoxy-7-methoxy-1-benzo[b]thiophene-2-carboxylic acid asfine white crystals. M.S. m/z 260 (M−1)⁺.

(e)3-Isopropoxy-7-methoxy-N-(1H-1,2,3,4-tetrazol-5-yl)-1-benzo[b]thiophene-2-carboxamide(VIB 090)

3-Isopropoxy-7-methoxy-1-benzo[b]thiophene-2-carboxylic acid (70.0 mg,0.26 mmol) was dissolved in anhydrous THF (2.0 mL) and CDI (55.0 mg,0.34 mmol) was added and the reaction mixture was heated to reflux for75 minutes. The reaction mixture was allowed to cool and 5-aminotetrazole (25.0 mg, 0.3 mmol) was added and the reaction mixture washeated to reflux overnight. The reaction mixture was allowed to cool andthen poured into water (30.0 mL). The aqueous reaction mixture wasacidified with concentrated hydrochloric acid and a precipitate formedand was collected by filtration, washed well with water, dried andrecrystallised from methanol/water to afford (74.3 mg, 85.0%) of thedesired3-isopropoxy-7-methoxy-N-(1H-1,2,3,4-tetrazol-5-yl)-1-benzo[b]thiophene-2-carboxamide(VIB 090) as yellow needles. M.S. m/z 332 (M−1)⁺.

Preparation of3-Isopropoxy-4-nitro-5-methoxy-N-(1H-1,2,3,4-tetrazol-5-yl)-1-benzo[b]thiophene-2-carboxamide(VIB-092) (a) 3-Chloro-5-methoxy-1-benzo[b]thiophene-2-carbonyl chloride

3-Methoxy cinnamic acid (5.0 g, 28.0 mmol) was added to anhydrouspyridine (230.0 mL) and anhydrous N,N-dimethylformamide (2.15 mL) andanhydrous chlorobenzene (40.0 mL) and thionyl chloride (10.5 mL, 0.14mol) was then added dropwise and the reaction mixture was heated toreflux for 24 hours. The reaction mixture was cooled and the solventevaporated under reduced pressure. Attempts to recrystallise the residuefrom t-BuOCH₃ and (THF/hexane) were unsuccessful. As such the residuewas redissolved in THF, filtered and the THF was evaporated underreduced pressure to afford (7.0 g, 97.0%) of the desired3-chloro-5-methoxy-1-benzo[b]thiophene-2-carbonyl chloride as a yellowsolid. M.S. m/z 260 (M)⁺. ¹H NMR (CDCl₃) δ 3.73 (3H, s, OCH₃), 3.93 (3H,s, OCH₃), 6.9 (1H, m, ArH), 7.05 (1H, s, ArH), 7.6 (1H, m, ArH).

(b) Isopropyl 3-chloro-5-methoxy-1-benzo[b]thiophene-2-carboxylate

3-Chloro-5-methoxy-1-benzo[b]thiophene-2-carbonyl chloride (7.32 g, 28.1mmol) was dissolved in a solution of anhydrous THF (30.0 mL) andisopropanol (30.0 mL) was added and the reaction mixture was heated toreflux for 5 hours. The reaction mixture was allowed to cool and thesolvent evaporated under reduced pressure to afford a residue which waspurified by column chromatography eluting with (dichloromethane/hexane)(3/7) to afford (1.39 g, 17.0%) of the desired isopropyl3-chloro-5-methoxy-1-benzo[b]thiophene-2-carboxylate as a white powder.m.p.=76-80° C., M.S. m/z 285 (M+1)⁺. ¹H NMR (CDCl₃) δ 1.33 (6H, d,CH(CH₃)₂, J=6.24 Hz), 3.85 (3H, s, OCH₃), 5.21 (1H, m, CH(CH₃)₂, J=624Hz), 7.09 (1H, dd, ArH, J=2.49, 8.85 Hz), 7.26 (1H, d, ArH, J=2.46 Hz),7.59 (1H d, ArH, J=8.85 Hz).

(c) Isopropyl 3-isopropoxy-5-methoxy-1-benzo[b]thiophene-2-carboxylate

Sodium hydride (60% dispersion) (600.0 mg, 4.0 mmol) was suspended inanhydrous THF (2.0 mL) and stirred at room temperature under anatmosphere of nitrogen for 2 minutes. A solution of isopropanol (350.0mL, 4.6 mmol) dissolved in anhydrous THF (2.0 mL) was slowly added tothe sodium hydride in THF. The reaction mixture was stirred at roomtemperature for 1.5 hours, then a solution of isopropyl3-chloro-5-methoxy-1-benzo[b]thiophene-2-carboxylate (600.0 mg, 2.1mmol) in anhydrous THF (3.0 mL) was slowly added. The resultant reactionmixture was heated to reflux for 17 hours. The reaction mixture wascooled and the THF was evaporated under reduced pressure and theremaining residue was partitioned between hexane and water. The aqueousphase was extracted with hexane and the hexane phase was dried,filtered, and evaporated under reduced pressure to afford the desiredisopropyl 3-isopropoxy-5-methoxy-1-benzo[b]thiophene-2-carboxylate as aviscous yellow oil. M.S. m/z 309 (M+1)⁺. ¹H NMR (CDCl₃) δ 1.24 (6H, d,2×CH₃, j=3.84 Hz), 2.1 (6H, s, 2×CH₃, j=6.9 Hz), 3.89 (3H, s, OCH₃),7.05 (1H, ArH, J=11.1 Hz).

(d) 3-Isopropoxy-5-methoxy-1-benzo[b]thiophene-2-carboxylic acid

Isopropyl 3-isopropoxy-5-methoxy-1-benzo[b]thiophene-2-carboxylate(649.0 mg, 2.1 mmol) was dissolved in methanol (2.5 mL) and aqueous 1Nsodium hydroxide (7.0 mL) was added and the reaction mixture was heatedto reflux for 7 hours. The reaction mixture was allowed to cool and thereaction mixture was poured into water. The aqueous solution was thenextracted with dichloromethane and the aqueous phase was acidified andextracted with dichloromethane. The dichloromethane extracts of theacidified aqueous phase were combined, dried, filtered and evaporatedunder reduced pressure to afford a residue, which was recrystallisedfrom acetonitrile to afford (148.0 g, 25.0%) of the desired3-isopropoxy-5-methoxy-1-benzo[b]thiophene-2-carboxylic acid as paleyellow fluffy crystals. m.p.=76-80° C., M.S. m/z 284 (M)⁺. ¹H NMR(CDCl₃) δ 3.85 (3H, s, OCH₃), 7.09 (1H, dd, ArH, J=2.49, 8.85 Hz), 7.26(1H, d, ArH, J=2.46 Hz), 7.59 (1H, d, ArH, J=8.85 Hz). Found C, 54.53,H, 4.58%, C13H₁₃ClO₃S requires C, 54.93, H, 4.53%. H.P.L.C. retentiontime=5.37 minutes. Linear Gradient over 10 minutes. 10 B/90 D to 90B/10D (B=90% CH₃CN/10% H₂O), (D=0.1N NH₄OAc (pH=4)).

(e) 3-Isopropoxy-4-nitro-5-methoxy-1-benzo[b]thiophene-2-carboxylic acid

3-Isopropoxy-5-methoxy-1-benzo[b]thiophene-2-carboxylic acid (200.0 mg,0.75 mmol) was added to acetic acid (5.0 mL) and concentrated nitricacid (1.0 mL) and the reaction mixture was stirred at between 0 and 5°C. in an icebath for 66 minutes. The yellow solution was poured intowater (75.0 mL) and the yellow precipitate was collected by filtration,washed well with water and dried to afford a yellow powder, which wasrecrystallised from (dichloromethane/hexane) to afford (129.0 mg, 55.0%)of the desired3-isopropoxy-4-nitro-5-methoxy-1-benzo[b]thiophene-2-carboxylic acid asyellow crystals. m.p.=197-200□C., M.S. m/z 312 (M+1)⁺. ¹H NMR (CDCl₃)δ1.32 (6H, d, CH(CH₃)₂, J=6.09 Hz), 3.99 (3H, s, CH₃), 5.02 (1H, m,CH(CH₃)₂, J=6.12 Hz), 7.32 (1H, d, ArH, J=9.0 Hz), 7.81 (1H, d, ArH,J=8.97 Hz). Found C, 50.13, H, 4.17; N, 4.42%, C₁₃H₁₃NO₆S requires C,50.16, H, 4.21; N, 4.5%. H.P.L.C. retention time=6.39 minutes. 10 B/90 Dto 90 B/10D (B=90% CH₃CN/10% H₂O), (D=0.1N NH₄OAc (pH=4)).

(f)3-Isopropoxy-4-nitro-5-methoxy-N-(1H-1,2,3,4-tetrazol-5-yl)-1-benzo[b]thiophene-2-carboxamide(VIB-092)

3-Isopropoxy-4-nitro-5-methoxy-1-benzo[b]thiophene-2-carboxylic acid(100.0 mg, 0.32 mmol) was dissolved in anhydrous THF (2.0 mL) and CDI(62.0 mg, 0.38 mmol) was added and the reaction mixture was heated toreflux for 90 minutes. The reaction mixture was allowed to cool and5-amino tetrazole (30.0 mg, 0.35 mmol) was added and the reactionmixture was heated to reflux for a further 4 hours. The reaction mixturewas allowed to cool and a yellow precipitate formed and was collected byfiltration, washed well with water and dried to afford (50.0 mg, 41.0%)of the desired3-isopropoxy-4-nitro-5-methoxy-N-1H-1,2,3,4-tetrazol-5-yl)-1-benzo[b]thiophene-2-carboxamide(VIB-092) as a yellow powder. m.p.=236-238° C., M.S. m/z 378 (M+1)⁺. ¹HNMR (DMSO-d₆) δ1.15 (6H, d, CH(CH₃)₂, J=6.06 Hz), 3.97 (3H, s, OCH₃),4.5 (1H, m, CH(CH₃)₂, J=6.03 Hz), 7.64 (1H, d, ArH, J=9.12 Hz), 8.25(1H, d, ArH, J=9.09 Hz). Found C 55.62, H 5.09, N, 4.94, %, C13H₁₅NO₄Srequires C, 55.5, H, 5.37; N, 4.98%. Found (M+1)⁺=282.08002 C₁₃H₁₅NO₄Srequires (M+1)⁺=282.08000.

Preparation of 3-(2-Hydroxyphenyl) buten-2-oic acid (VIB 297) (a)5-(-Methyl-3-hydroxybenzylidine)rhodanine

Rhodanine (2.0 g, 15.0 mmol), was added to a stirred solution ofammonium acetate (120.0 mg) and glacial acetic acid (360.0 mL) inbenzene (13.0 mL). The reaction mixture was stirred to boiling for 5minutes. 3-Hydroxyacetophenone (2.0 g, 145.7 mmol) was then added to thereaction mixture and the flask was connected to a Dean Stark trap. Thereaction mixture was then heated to reflux overnight, then allowed tocool to room temperature after which a yellow precipitate formed. Theprecipitate was then collected by filtration, washed with water andpurified by recrystallisation from (methanol/water) to afford (2.17 g,59.0%) of the desired product as a yellow powder. M.p.=201-202° C., M.S.m/s 252 (M+1)⁺. 1H NMR (DMSO) δ 2.51 (6H, d, CH(CH₃)₂, J=6.18 Hz), 3.40(3H, s, OCH₃), 3.88 (3H, s, SO₂CH₃), 4.94 (1H, pent, CH(CH₃)₂, J=6.18Hz), 7.12-7.16 (2H, m, 2×ArH), 7.66 (1H, d, ArH, f=5.61 Hz), 9.98 (1H,s, NH).

(b) 3-(2-Hydroxyphenyl) buten-2-oic acid. (VIB-297)

5-(-Methyl-3-hydroxybenzylidine)rhodanine (300.0 mg, 1.2 mmol), wasadded to a stirred solution of potassium hydroxide (340.0 mg, 6.0 mmol)in methanol (20.0 mL). The reaction mixture was stirred at roomtemperature for 2 hours. The reaction mixture was then slowly acidifiedwith glacial acetic acid. The yellow precipitate was collected byfiltration and purified by recrystallisation from propanol to afford(241.0 mg, 97.9%) of the desired product (VIB 297) as yellow crystals.M.S. m/s 211 (M+1)⁺. ¹H NMR (DMSO) δ 2.51 (6H, d, CH(CH₃)₂, J=6.18 Hz),3.4 (3H, s, OCH₃), 3.88 (3H, s, SO₂CH₃), 4.94 (1H, pent, CH(CH₃)₂,J=6.18 Hz), 7.12-7.16 (2H, m, 2×ArH), 7.66 (1H, d, ArH, J=5.61 Hz), 9.98(1H, s, NH).

Preparation of3-Cyclohexyloxy-5-methoxy-1-benzo[b]thiophene-2-carboxylic acid(VIB-276)

Cyclohexyl 3-cyclohexyloxy-5-methoxy-1-benzo[b]thiophene-2-carboxylate(3.0 g, 7.72 mmol) was dissolved in methanol (60.0 mL) and water (15.0mL) and sodium hydroxide (8.0 g, 0.2 mol) was added and the reactionmixture was heated to reflux for 17.0 hours. A colourless fluffy solidprecipitated. The reaction mixture was allowed to cool and theprecipitate was collected by filtration and then stirred with 1N aqueoushydrochloric acid (50.0 mL) and the resulting solid was collected byfiltration and purified by recrystallisation from methanol/water toafford (2.3 g, 97.2%) of the desired3-cyclohexyloxy-5-methoxy-1-benzo[b]thiophene-2-carboxylic acid as smallwhite crystals. m.p.=176-177° C., M.S. m/z 307 (M+1)⁺. ¹H NMR (CDCl₃)δ1.26-1.40 (6H, m, 3×CH), 1.61-1.73 (3H, m, 3×CH), 1.84-1.88 (2H, m,2×CH), 2.11-2.15 (2H, m, 2×CH), 3.91 (3H, s, OCH₃), 4.56 (1H, m,CH(CH₃)₂, J=4.08 Hz), 7.16 (1H, dd, ArH, J=2.49, 8.85 Hz), 7.26 (1H, m,ArH), 7.65 (1H, d, ArH, J=5.01. Hz). Found C 62.62, H 5.98%. C₁₆H₁₈O₄Srequires C 62.72, H 5.92%. H.P.L.C. retention time=6.56 minutes. (10%B/90 D) to (90% B/10% D) over 20 minutes (B=90% CH₃CN 10% H₂O) (D=0.1NNH₄OAc (pH=4)).

Preparation of 3-Chloro-6-nitro-1-benzo[b]thiophene-5-oxo-2-carboxylicacid (VIB-044)

30% Aqueous hydrogen peroxide (9.2 mL, 81.0 mmol) was added to3-chloro-6-nitro-1-benzo[b]thiophene-2-carboxylic acid (500.0 mg, 1.94mmol) dissolved in acetic acid (19.3 mL) and the reaction mixture wasstirred at room temperature for 24 hours. The reaction mixture wasdiluted with water and the aqueous phase was extracted withdichloromethane and the dichloromethane phase was washed with brine,water and saturated aqueous NaHCO₃ solution. The dichloromethane phasewas then dried, filtered and evaporated under reduced pressure to affordan off white solid, which was purified by column chromatography elutingwith (ethyl acetate/hexane/acetic acid) (40/40/10) to afford the desired3-chloro-6-nitro-1-benzo[b]thiophene-S-oxo-2-carboxylic acid.

Preparation of 3-Chloro-6-nitro-1-benzo[b]thiophene-2-carboxylic acid(V.I.B-026)

(a) Methyl 3-chloro-6-nitro-1-benzo[b]thiophene-2-carboxylate)

4-Nitro cinnamic acid (10.0 g, 52.0 mmol) was dissolved in anhydrous DMF(4.0 mL) and chlorobenzene (70.0 mL) and anhydrous pyridine (410.0 mL)was added. To this reaction mixture thionyl chloride (19.0 mL, 260.0mmol) was added dropwise over 30 minutes at room temperature. Thereaction mixture was heated at reflux for 24 hours. A precipitate formedafter about 3 hours and the reaction mixture gradually became a browncolour. The reaction mixture was allowed to cool to room temperature andthen to about 0° C. in ice. The precipitate was collected by filtration,washed well with diethyl ether and dried to afford (6.0 g, 44.0%) of thedesired 3-chloro-6-nitro-1-benzo[b]thiophene-2-carbonyl chloride. The3-chloro-6-nitro-1-benzo[b]thiophene-2-carbonyl chloride (6.0 g, 22.0mmol) was suspended in anhydrous THF (180.0 mL) and methanol (120.0 mL)was added dropwise over 1 hour and the greenish suspension was stirredfor 6 hours. The solvent was evaporated under reduced pressure and theresidue was subject to rapid silica filtration eluting withdichloromethane. The yellow eluent was evaporated under reduced pressureand the yellow residue was purified by recrystallisation from ethylacetate to afford (5.2 g, 37.0%) of the desired methyl3-chloro-6-nitro-1-benzo[b]thiophene-2-carboxylate as dark yellow/greenprisms. m.p.=216-217° C., M.S. m/z 271 (M+1)⁺. ¹H NMR (CDCl₃) δ 4.0 (3H,s, OCH₃), 8.12 (1H, d, ArH, J=8.94 Hz), 8.35 (1H, dd, ArH, J=1.92, 8.91Hz), 8.78 (1H, d, ArH, J=1.89 Hz). Found C, 44.18, H, 2.19; N, 5.19%,C₁₀H₆ClNO₄S requires C, 44.28, H, 2.21, N, 5.17%.

(b) 3-Chloro-6-nitro-1-benzo[b]thiophene-2-carboxylic acid (V.I.B-026)

Methyl 3-chloro-6-nitro-1-benzo[b]thiophene-2-carboxylate (46.2 mg, 0.17mmol) was dissolved in ethanol (2.0 mL) and aqueous 2N NaOH (0.5 mL) wasadded. The reaction mixture was heated to reflux for 1.0 hour and thenallowed to cool to room temperature and stirred at room temperature for48 hours. The solvent was evaporated under reduced pressure to afford awhite residue which was taken up in water and acidified, then extractedwith ethyl acetate, dried and evaporated under reduced pressure toafford a (30.0 mg, 68.7%) of the desired3-chloro-6-nitro-1-benzo[b]thiophene-2-carboxylic acid as white powder.M.S. m/z 255.71 (M−1)⁺. ¹H NMR (300.13, d₆-DMSO) δ 8.14 (1H, m, ArH),8.35 (1H, m, ArH), 9.20 (1H, m, ArH).

Preparation of 3-[(3-Carboxyphenyl)sulfinyl]benzenecarboxylic acid(V.I.B-032) (a) 3-[(Carboxyphenyl)sulfanyl]benzenecarboxylic acid.(V.I.B-006)

To a solution of 3-iodobenzoic acid (24.8 g, 100.0 mmol) was dissolvedin anhydrous DMF (100.0 mL) was added potassium carbonate (6.9 g, 50.0mmol). The reaction mixture was heated to 100° C. for 5 minutes andsodium sulphide (4.3 g, 55.0 mmol) and copper iodide (1.9 g, 10.0 mmol)was added and the reaction mixture was heated to reflux under anatmosphere of nitrogen for 12 hours. Water (500.0 mL) was then added andthe reaction mixture was heated to boiling with activated carbon. Thecarbon was filtered off while hot into an excess of 6N HCl (50.0 mL). Aprecipitate formed on cooling to room temperature and was collected byfiltration and washed with water to afford (5.36 g, 19.5%) of thedesired 3-[(carboxyphenyl)sulfanyl]benzenecarboxylic acid (GM71/7) as anoff-white powder. M.S. m/z 272.73 (M−1)⁺. ¹H NMR (300.13, d₆-DMSO)7.32-7.63 (4H, m, 4×ArH), 7.84-7.99 (4H, m, 4×ArH).

(b) 3-[(3-Carboxyphenyl)sulfinyl]-benzenecarboxylic acid (V.I.B-032)

To a stirred ice cooled solution of 3-[(carboxyphenyl)sulfanyl]benzenecarboxylic acid (GM71/7, VIB-006) (1.0 g, 3.65 mmol) in aqueouspyridine ((1/1) 5.84 mL), phenyl trimethylammonium tribromide (1.43 g,3.8 mmol) was gradually added in portions to keep the temperaturebetween 0 and 10° C. When addition was complete, the reaction mixturewas stirred at room temperature for 24 hours. Then the unreacted PTABwas decomposed with 40% NaHSO₃ (3.65 mL). Ice water (14.6 mL) was thenadded and the reaction mixture was acidified with 2NH₂SO₄. A solidprecipitated to afford (833.0 mg, 78.7%) of the desired3-[(3-Carboxyphertyl)sulfinyl]benzenecarboxylic acid (GM71/21, VIB-032)as a white powder. M.S. m/z 288.70 (M−1)⁺. ¹H NMR (300.13, d₆-DMSO) 7.67(2H, t, 2×ArH, J=7.8 Hz), 7.99 (4H, m, 4×ArH), 8.23 (2H, m, 2×ArH). ¹HNMR (300.13, d₆-DMSO) 38.8, 132.2, 133.1, 133.4, 139.5. Found C, 53.97,H, 3.22%, C₁₄H₁₀O₅S. 1.0 H₂O requires C, 54.49, H, 3.24%.

(Reference: Rabai, J., Kapovits, I., Tanacs, B and Tamas, J., Synthesis,1990, 847-849. Preparation of 3-(2-Oxophenylethylsulfanyl)benzoic acid(VIB-294)

To bromoacetophenone (250 mg, 1.16 mmole) and anhydrous K₂CO₃ (694 mg,5.02 mmole) in ethanol, 193.6 mg (1.25 mmole) 3-mercaptobenzoic acid wasadded and the mixture refluxed overnight. The solvent was evaporated andwater added to the solid residue. The basic aqueous solution wasextracted with ethyl acetate to remove unreacted bromoacetophenone. Theaqueous layer was acidified and extracted with ethyl acetate, dried,evaporated and the residue purified by flash chromatography usingchloroform:methanol 95:5. Evaporation of the fractions resulted in ayellow powder (380 mg). M.S. m/s 271 (M−1)⁺. ¹H NMR (DMSO) δ4.75 (2H, s,—CH₂—), 7.39-7.7 (4H, m, 4×ArH), 7.75 (1H, d, ArH, J=5.61 Hz), 7.86 (1H,s, ArH), 8.02 (3H, d, ArH).

Preparation of 3-[2-(3-Cyanophenyl)-2-oxoethylsulfanyl]benzoic acid (VIB216)

3-acetylbezonitrile (2.5 g, 0.017 mole) was dissolved in acetic acid (50ml) then bromine liquid (3 gm, 0.0187 mole) in acetic acid (12.5 ml) wasadded dropwise over 2 hrs. The reaction mixture was stirred overnight.The acetic acid was evaporated to yield a fawn coloured solid (3.63 gm).This was used in the next step without further purification.

Bromoacetylbenzonitrile (300 mg, 1.34 mmole) and anhydrous K₂CO₃ (740mg, 5.35 mmole) in ethanol, 210 mg (1.36 mmole) 3-mercaptobenzoic acidwas added and the mixture refluxed overnight. The solvent was evaporatedand water added to the solid residue. The basic aqueous solution wasextracted with ethyl acetate to removeunreacted-bromoacetylbenzonitrile. The aqueous layer was acidified andextracted with ethyl acetate, dried, evaporated and the residue purifiedby flash chromatography using chloroform followed by chloroform:methanol(99:1). Evaporation of high Rf yellow fractions resulted in a yellowpowder (130 mg). M.S. m/s 296 (M−1)⁺. ¹H NMR (DMSO) δ 4.31 (2H, s,—CH₂—), 7.25-8.25 (8H, m, 8×ArH).

2-[3-Oxo-3-(1H-pyrrol-2-yl)propenyl]benzoic acid (VIB 238)

1 gm (6.7 mmole) 2-carboxybenzaldehyde and 2-acetylindole (726.8 mg, 6.7mmole) were dissolved in absolute ethanol (16 ml) and NaOH (25%, 16 ml)was added and stirred overnight. The reaction mixture was added to waterand extracted with ethyl acetate to remove unreacted 2-acetylindole. Theaqueous solution was acidified and extracted with ethyl acetate. Theethyl acetate extract was washed with water, dried and evaporated toyield the chalcone (1.28 gm).

Preparation of 3-(3-Cyanopropylsulfanyl)benzoic acid (VIB 239)

To solution of 3-mercaptobenzoic acid (250 mg, 1.62 mmole) in ethanol(10 ml), anhydrous potassium carbonate (896 mg, 6.48 mmole) was addedfollowed by bromobutyronitrile (239.97 mg, 1.62 mmole). The reactionmixture was refluxed overnight. The ethanol was evaporated and wateradded. The basic solution was extracted with ethyl acetate. The aqueouslayer was acidified and the resulting precipitate filtered and dried toyield 196 mg product. M.S. m/s 220 (M−1)⁺. ¹H NMR (DMSO) 81.79 (2H, m,—CH₂—), 2.37 (2H, t, —CH₂—), 3.02 (2H, t, CH₂), 7.56 (1H, d, 1×ArH),7.74 (1H, d, 1×ArH), 7.83 (1H, bs, 1H, 1×ArH).

Preparation of 3-[2-Oxo-2-(3-carboxyphenyl)ethylsulfanyl]benzoic acid(VIB 217)

The nitrile (VIB 216) (100 mg, 0.316 mmole) was dissolved in acetic acid(3 ml), conc sulphuric acid (1 ml) and water (1 ml) and the mixturerefluxed overnight. A precipitate formed overnight. The mixture wasadded to water and extracted with ethyl acetate. The ethyl acetateextract was washed with water, dried and evaporated to yield the product(50 mg). M.S. m/s 314 (M 2)⁺. ¹H NMR (DMSO) δ 4.57 (2H, s, —CH₂—),7.3-8.6 (8H, m, 8×ArH).

Preparation of1-(3-Carboxyphenyl)-2-[2-(3-carboxyphenyl)-2-oxoethylsulfanyl]ethanone(VIB 292)

To a suspension of sodium sulphide (100 mg, 1.28 mmole) in DMF (5 ml)was added 3-bromoacetylbenzonitrile (500 mg, 2.23 mmole) in DMF (2 ml)and the mixture stirred overnight. The DMF was evaporated and wateradded to the residue. The mixture was extracted with dichloromethane andthe extract washed with water, dried and evaporated to yield a brown oilwhich was used in the next step without purification.

The dinitrile (440 mg) was dissolved in acetic acid (6 ml), concsulphuric acid (2 ml) and water (2 ml) and refluxed overnight. Aprecipitate formed. The mixture was added to water and the brown solidfiltered and dried to yield product (200 mg). M.S. m/s 356 (M−2)⁺. ¹HNMR (DMSO) δ 4.24 (4H, s, 2×-CH₂—), 7.2-8.6 (8H, m, 8×ArH).

Preparation of 4-[(2-oxo-2-phenylethyl)thio]benzoic acid (VIB-384)

To bromoacetophenone (322.8 mg, 1.62 mmole) and anhydrous K₂CO₃ (896 mg,6.48 mmole) in ethanol (20 ml), 250 mg (1.62 mmole) 4-mercaptobenzoicacid was added and the mixture refluxed overnight. The solvent wasevaporated and water added to the solid residue. The basic aqueoussolution was extracted with ethyl acetate to remove unreactedbromoacetophenone. The aqueous layer was acidified to yield aprecipitate which was filtered and dried (356 mg). m/z 271 (M−1)+ 1H NMR(DMSO) δ 4.75 (2H, s, —CH2-), 7.35-7.72 (5H, m, 5×ArH), 7.82 (2H, d,2×ArH), 8.05 (2H, d, 2×ArH).

Preparation of 4-{[2-(3-cyanophenyl)-2-oxoethyl]thio}benzoic acid (VIB385)

To 3-cyanobromoacetophenone (363.3 mg, 1.62 mmole) and anhydrous K2CO3(896 mg, 6.48 mmole) in ethanol (20 ml), 250 mg (1.62 mmole)4-mercaptobenzoic acid was added and the mixture refluxed overnight. Thesolvent was evaporated and water added to the solid residue. The basicaqueous solution was extracted with ethyl acetate to remove unreactedbromoacetophenone. The aqueous layer was acidified to yield aprecipitate which was filtered and dried (377 mg). The solid was furtherpurified by flash chromatography (CHCl3:CH₃OH 99:1 to 95:5. Thehomogeneous fractions were pooled and evaporated to yield product (110mg). m/z 296 (M−1)+¹HNMR (DMSO) δ 4.9 (2H, s, —CH2-), 7.44 (2H, d,2×ArH), 7.63 (1H, d, ArH), 7.76 (1H, t, ArH), 7.83 (2H, d, 2×ArH), 7.93(1H, d, ArH), 8.13 (1H, d, ArH), 8.29 (1H, d, ArH), 8.54 (1H, d, ArH).

Preparation of 2-{[2-(4-carboxyphenyl)-2-oxoethyl]thio}benzoic add (VIB410)

To bromoacetophenone (394.09 mg, 1.62 mmole) and anhydrous K₂CO₃ (896mg, 6.48 mmole) in ethanol (20 ml), 250 mg (1.62 mmole)2-mercaptobenzoic acid was added and the mixture refluxed overnight. Thesolvent was evaporated and water added to the solid residue. The aqueouslayer was acidified to yield a precipitate which was filtered and dried(487 mg). m/z 315 (M−1)+¹HNMR (DMSO) δ 4.75 (s, 2H, —CH2-), 7.22 (1H, t,ArH), 7.47 (2H, t, 2×ArH), 7.87 (1H, d, ArH), 8.06 (2H, d, 2×ArH), 8.15(2H, d, 2×ArH).

Preparation of 2-{[2-(3-cyanophenyl)-2-oxoethyl]thio}benzoic acid (VIB411)

To 3-cyanobromoacetophenone (250 mg, 1.11 mmole) and anhydrous K2CO3(617 mg, 4.46 mmole) in ethanol (20 ml), 172 mg (1.11 mmole)2-mercaptobenzoic acid was added and the mixture refluxed overnight. Thesolvent was evaporated and water added to the solid residue. The basicaqueous solution was extracted with ethyl acetate to remove unreactedbromoacetophenone. The aqueous layer was acidified and, extracted withethyl acetate, washed, dried and evaporated to yield solid (290 mg). m/z296 (M−1)₄. ¹HNMR (DMSO) δ 4.75 (2H, s, —CH2-), 7.22 (1H, t, ArH), 7.49(2H, t, 2×ArH), 7.74 (1H, t, ArH), 7.88 (1H, d, ArH), 8.12 (1H, d, ArH),8.3 (1H, d, ArH), 8.54 (1H, s, ArH).

Preparation of 2-{[2-(3-carboxyphenyl)-2-oxoethyl]thio}benzoic add (VIB412)

To 3-carboxybromoacetophenone (250 mg, 1.03 mmole) and anhydrous K2CO3(568.6 mg, 4.11 mmole) in ethanol (20 ml), 158.6 mg (1.03 mmole)2-mercaptosuccinic acid was added and the mixture refluxed overnight.The solvent was evaporated and water added to the solid residue. Theaqueous layer was acidified and extracted with ethyl acetate, washed,dried and evaporated to yield solid (250 mg). m/z 315 (M−1)+ 1HNMR(DMSO) δ 4.75 (2H, s, —CH2-), 7.22 (2H, t, 2×ArH), 7.48 (2H, t, 2×ArH),7.67, 1H, t, ArH), 7.87 (1H, d, ArH), 8.2 (1H, d, ArH), 8.3 (1H, d,ArH), 8.53 (1H, s, ArH).

Preparation of 4-[(2E)-3-phenylprop-2-enoyl]benzoic acid (VIB 237)

To a mixture of 4-carboxyacetophenone (250 mg, 1.52 mmole) andbenzaldehyde (161.6 mg, 1.52 mmole) in absolute ethanol (4 NaOH (25%w/v, 4 ml) was added and allowed to stir at RT for 2 days. Water wasadded and the mixture acidified to pH 4. The precipitate was filtered,dried and recrystallized with methanol to yield product (98 mg). m/z 251(M−1)+ 1HNMR (DMSO) δ 7.4-7.92 (7H, m, ArH & ═CH), 8.09 (2H, d, 2×ArH),8.19 (2H, d, 2×ArH).

[3-(3-Hydroxyphenyl)-2-mercaptobut-2-enoylamino]acetic add (VIB-383)

5-(-Methyl-3-hydroxybenzylidine) rhodanine acetic acid (100.0 mg, 0.33mmol) was added to a solution of potassium hydroxide (90.7 mg, 1.62mmol) in methanol (10.0 mL). The reaction mixture was stirred at roomtemperature for 2 hours. The reaction mixture was then poured intosaturated sodium chloride (100.0 mL) and the resulting aqueous solutionwas acidified with glacial acetic acid. A yellow precipitate formed,which was collected by filtration and dried to afford a crude sample ofthe desired 3-(2-hydroxyphenyl) buten-2-oic acid as a yellow solid whichwas purified by recrystallisation from n-propanol to afford (253.6 mg,100.0%) of the desired 3-(2-hydroxyphenyl) buten-2-oic acid as a yellowpowder. M.S. m/z 266 (M−1)⁺. ¹H NMR (300.13 MHz, CD₃OD) δ 1.12 (3H, s,CH₃), 2.2 (2H, s, CH₂), 5.78 (3H, m, 3×ArH).

5-(-Methyl-3-hydroxybenzylidine)rhodanine-3-acetic acid (VIB-374)

Rhodanine-3-acetic acid (2.81 g, 14.7 mmol) was added to a stirringsolution of ammonium acetate (120.0 mg) and glacial acetic acid (360.0L) in anhydrous benzene (30.0 mL). The reaction mixture was stirred toboiling for 5 minutes. 3-Hydroxyacetophenone (2.0 g, 14.7 mmol) was thenadded to the reaction mixture and the flask was connected to a DeanStark trap. The reaction mixture was then heated to reflux overnight,then allowed to cool to room temperature after which the solvent wasevaporated under reduced pressure to afford a orange/red gum, which waspurified with column chromatography eluting with(chloroform/methanol/acetic acid) (95/5/10 drops) to afford the desired5-(-methyl-3-hydroxybenzylidine) rhodanine-3-acetic acid as a viscousred oil. M.S. m/z 307 (M−2)⁺. ¹H NMR (DMSO-d₆) δ 1.9 (3H, s, CH₃), 2.7(2H, s, CH₂), 6.85 (2H, m, 2×ArH), 7.28 (1H, m, ArH), 8.28 (1H, s, OH).

4-Phenethyloxycinnamic acid (VIB-299)

Aqueous 1N Sodium hydroxide solution (6.0 mL, 12.0 mmol) was added to asolution of 4-hydroxycinnamic acid (536.0 mg, 3.2 mmol) in ethanol (10.0mL). 2-Bromoethylbenzene (575.0 mg, 3.1 mmol) was then added to thereaction mixture and the resulting reaction mixture was stirred at roomtemperature overnight. The solvent was evaporated under reduced pressureto afford a white residue, which was taken up in water. The aqueousphase was then acidified with concentrated hydrochloric acid to producea white precipitate which was isolated by filtration and washed withwater, then dried to afford (544.0 mg, 66.8%) of the desired4-phenethyloxycinnamic acid as a white powder. ¹H NMR (300 MHz, DMSO) δ3.82 (3H, s, OCH₃), 4.78 (2H, s, CH₂), 6.92 (2H, d, 2×ArH, J=7.5 Hz),7.16 (2H, d, 2×ArH, J=7.5 Hz), 7.52-7.60 (1H, m, ArH), 7.62-7.72 (1H, m,ArH), 7.98 (1H, m, ArH).

Preparation of 3-Benzyloxy-1-benzo[b]thiophene-2-carboxylic acid (VIB333) (a) Methyl 3-hydroxy-1-benzo[b]thiophene-2-carboxylate

Potassium tertiary butoxide (3.7 g, 32.9 mmol) was added to a solutionof methyl thiosalicylate (5.0 g, 29.7 mmol) dissolved in anhydrous THF(40.0 mL). The resultant yellow suspension was stirred at roomtemperature for 30 minutes at room temperature. Methyl chloroacetate(2.86 mL, 32.6 mmol) was then added dropwise to the reaction mixture andthe reaction mixture was stirred at room temperature for 15 minutes andthen heated to reflux for 35 minutes. The reaction mixture was thenallowed to cool to approximately 40° C. and another batch of potassiumtertiary butoxide (3.7 g, 32.9 mmol) was added and the reaction mixturewas allowed to heat to reflux for 20 hours. aqueous 2.5N sodiumhydroxide (30.0 mL) was added and the reaction mixture was heated toreflux overnight. The reaction mixture was allowed to cool and themethanol was evaporated under reduced pressure to afford a white residuewhich was taken up in water and the aqueous solution was acidified withconcentrated hydrochloric acid and a pink solid precipitated and wascollected by filtration. The pink product was purified byrecrystallisation from methanol with the addition of charcoal to afford(912.6 mg, 64.0%) of the desired3-benzyloxy-1-benzo[b]thiophene-2-carboxylic acid as white crystals.M.S. m/z 382 (M+1)⁺. ¹H NMR (CDCl₃) δ 3.62 (3H, s, OCH₃), 5.19 (2H, s,OCH₂), 6.49 (1H, m, ArH, 6.7 (1H, m, ArH), 6.78-6.82 (2H, m, 2×ArH),6.88-7.15 (3H, m, 3×ArH), 7.62 (1H, m, ArH), 10.05 (1H, s, NH).

(b) Methyl 3-benzyloxy-1-benzo[b]thiophene-2-carboxylate

Potassium carbonate (4.1 g, 29.6 mmol) was added as a solid to asolution of 3-hydroxy-1-benzo[b]thiophene-2-carboxylate (1.4 g, 6.7mmol) and benzyl bromide (1.2 mL, 10.1 mmol) in anhydrous DMF (15.0 mL)at room temperature. The reaction mixture was heated at 60° C.overnight. The reaction mixture was allowed to cool to room temperature,filtered and the DMF was evaporated under reduced pressure to afford ayellow solid which was purified with column chromatography eluting with(ethyl acetate/hexane) (1/19) to afford a white powder which was furtherpurified by recrystallisation from hexane to afford (2.84 g, 66.0%) ofthe desired methyl 3-benzyloxy-1-benzo[b]thiophene-2-carboxylate asfluffy white needles. M.S. m/z 382 (M+1)⁺. ¹H NMR (DMSO-d₆) δ 3.8 (2H,s, OCH₂); 3.81 (3H, s, OCH₃), 7.01-7.04 (2H, m, 2×7.05-7.40 (2H, m,2×ArH), 7.57-7.67 (4H, m, 4×ArH), 8.81 (1H, s, NH).

(c) 3-Benzyloxy-1-benzo[b]thiophene-2-carboxylic acid (VIB 333)

Methyl 3-benzyloxy-1-benzo[b]thiophene-2-carboxylate (1.5 g, 5.0 mmol)was dissolved in methanol (50.0 mL) and aqueous 2.5N sodium hydroxide(30.0 mL) was added and the reaction mixture was heated to refluxovernight. The reaction mixture was allowed to cool and the methanol wasevaporated under reduced pressure to afford a white residue which wastaken up in water and the aqueous solution was acidified withconcentrated hydrochloric acid and a pink solid precipitated and wascollected by filtration. The pink product was purified byrecrystallisation from methanol with the addition of charcoal to afford(912.6 mg, 64.0%) of the desired3-benzyloxy-1-benzo[b]thiophene-2-carboxylic acid as white crystals.M.S. m/z 382 (M+1)⁺. ¹H NMR (CDCl₃) δ 3.62 (3H, s, OCH₃), 5.19 (2H, s,OCH), 6.49 (1H, m, ArH, 6.7 (1H, m, ArH), 6.78-6.82 (2H, m, 2×ArH),6.88-7.15 (3H, m, 3×ArH), 7.62 (1H, m, ArH), 10.05 (1H, s, NH).

Throughout this specification the word “comprise”, or variations such as“comprises” or “comprising”, will be understood to imply the inclusionof a stated element, integer or step, or group of elements, integers orsteps, but not the exclusion of any other element, integer or step, orgroup of elements, integers or steps.

All publications mentioned in this specification are herein incorporatedby reference. Any discussion of documents, acts, materials, devices,articles or the like which has been included in the presentspecification is solely for the purpose of providing a context for thepresent invention. It is not to be taken as an admission that any or allof these matters form part of the prior art base or were common generalknowledge in the field relevant to the present invention as it existedin Australia or elsewhere before the priority date of each claim of thisapplication.

It will be appreciated by persons skilled in the art that numerousvariations and/or modifications may be made to the invention as shown inthe specific embodiments without departing from the spirit or scope ofthe invention as broadly described. The present embodiments are,therefore, to be considered in all respects as illustrative and notrestrictive.

TABLE 1 Fc Receptor Modulating Compounds According to the PresentInvention Concentration at 50% inhibition of platelet Compoundactivation by Name Structure HAGG (micM) 001

600 026

100 032

70 044

230, 230 090

195, 295 092

630, 435 216

240, 240 217

360, >630 238

270 239

330 261

<140 (IC67) 276

<165 (IC79), 170 294

<190 (IC89), 135, 155 297

190 299

410 237

40 410

50 411

180 412

60 294

80 350

290 383

280 333

520 384

170 385

360 027

0, 84, 49 076

13 080

Insoluble 081

83 100

7 114

8 192

22, 19 197

91, 26, 87, 93 200

98, 54, 95 219

Not yet tested 233

74, 67, 87, 24, 74 234

25, 54, 27 235

30, 49, 54 236

34, 33, 65 255

11, 25, 21, 39 331

17, 58, 37 336

15, 65, 53 337

4, 5, −45 338

10, 43, 27 339

0, 46, 35 340

2, 54, 46 341

9, 66, 62 343

0, 39, 25 344

2, 42, 28 355

6, 43, 9 342

26, 80, 76

TABLE 2 Summary of most active small molecule inhibitors IN VIVO TESTINGDose IN VITRO TESTING Schedule 1 Dose IC50 (7.5 mg/day Schedule 2 ELISAPlatelet Inhibition on days 0.33 mg/ Compound (mM) (mM) 21, 24, 27, 30)(day 21-34) VIB001 12.2 0.61 VIB032 2.8 −'ve yes VIB153 8.4 0.56 yes yesVIB238 17.5 0.27 yes VIB237 6.2 0.04 VIB113 8.4 1.20 yes yes VIB152 1.80.31 yes VIB197 9.4 1.30 yes yes VIB216 3.0 0.25 VIB217 6.1 0.32 VIB2946.0 0.08 yes VIB384 4.8 0.17 yes VIB385 6.8 0.36 yes VIB410 6.9 0.05VIB411 7.8 0.18 VIB412 7.0 0.06 VIB239 −'ve 0.33 VIB292 5.6 0.52 VIB2975.6 0.19 yes VIB299 7.2 0.41 yes VIB350 1.3 0.29 VIB383 1.0 0.28 VIB3331.6 0.52 VIB026 17.5 0.78 VIB374 2.0 0.22

1. A compound having the general formula I:

wherein R1, R2, R3, R4, R5, are each independently selected from H,halogen, NO₂, CN, C₁₋₆ alkyl, CF₃, aryl, heteroaryl, cycloalkyl,cycloheteroalkyl, OCF₃, OR18, SR18, OC₁₋₆ alkyl, OC₂₋₆alkylNR18R19,Oaryl, Oheteroaryl, Ocycloalkyl, Ocycloheteroalkyl, OC₁₋₆alkylaryl,OC₁₋₆alkylheteroaryl, OC₁₋₆alkylcycloalkyl, OC₁₋₆ cycloheteroalkyl,CO₂R18, C₁₋₆ alkylCO₂R18, CONR18R19, C₁₋₆ alkylCONR18R19, NR18R19, C₁₋₆alkylNR18R19, NR20C₁₋₆ alkylNR18R19, C₁₋₆ alkylNR20C₁₋₆alkylNR18R19,NR18COR19, C₁₋₆ alkylNR18COR19, C₁₋₆ alkylNR20CONR18R19, NR20CONR18R19,C₁₋₆ alkylNR18SO₂R19, NR18SO₂R19; R18 and R19 are each independentlyselected from H, C₁₋₄ alkyl, C₁₋₄ alkyl cycloheteroalkyl, aryl,heteroaryl, C₁₋₄ alkyl aryl, C₁₋₄ alkyl heteroaryl, or may be joined toform an optionally substituted 3-8 membered ring optionally containingan atom selected from O, S, NR21; R20, R21 are each independentlyselected from H, C₁₋₄ alkyl; R6 is selected from H, C₁₋₄ alkyl, R7 isselected from H, C₁₋₄ alkyl, SH, CN; R8 is selected from OR9, NR9R10;R9, R10 are each independently selected from H, C₁₋₄ alkyl, C₁₋₄alkylCO₂H, C₁₋₄ alkyl cycloheteroalkyl, aryl, heteroaryl, C₁₋₄ alkylaryl, C₁₋₄ alkyl heteroaryl, or may be joined to form an optionallysubstituted 3-8 membered ring optionally containing an atom selectedfrom O, S, NR11; R11 is selected from H, C₁₋₄ alkyl.
 2. A compoundaccording to claim 1 wherein R1, R2, R3, R4 and R5, are eachindependently selected from H, OH, OC₁₋₄alkyl, OC₁₋₄ alkylaryl,C₁₋₄alkyl, halogen; R6 is selected from H, R7 is selected from H, SH,CN; R8 is selected from OH, NR9R10; R9, R10 are each independentlyselected from H, C₁₋₄ alkyl, C₁₋₄alkylCO₂H.
 3. A compound having thegeneral formula II:

wherein R1, R2, R3, R4, R5, R6, R7, R8, R9, and R10 are eachindependently selected from H, halogen, NO₂, CN, C₁₋₆ alkyl, CF₃, aryl,heteroaryl, cycloalkyl, cycloheteroalkyl, OCF₃, OR18, SR18, OC₁₋₆ alkyl,OC₂₋₆ alkylNR18R19, Oaryl, Oheteroaryl, Ocycloalkyl, Ocycloheteroalkyl,OC_(—)6 alkylaryl, OC₁₋₆ alkylheteroaryl, OC₁₋₆alkylcycloalkyl, OC₁₋₆cycloheteroalkyl, CO₂R18, C₁₋₆ alkylCO₂R18, CONR18R19, C₁₋₆alkylCONR18R19, NR18R19, C₁₋₆ alkylNR18R19, NR20C₁₋₆alkylNR18R19, C₁₋₆alkylNR20C₁₋₆ alkylNR18R19, NR18COR19, C₁₋₆ alkylNR18COR19, C₁₋₆alkylNR20CONR18R19, NR20CONR18R19, C₁₋₆ alkylNR18SO₂R19, NR18SO₂R19;R18, R19 are each independently selected from H, C₁₋₄ alkyl, C₁₋₄ alkylcycloheteroalkyl, aryl, heteroaryl, C₁₋₄ alkyl aryl, C₁₋₄ alkylheteroaryl, or may be joined to form an optionally substituted 3-8membered ring optionally containing an atom selected from O, S, NR21;R20, R21 are each independently selected from H, C₁₋₄ alkyl; R11R, R12are each independently selected from H, C₁₋₄ alkyl, halogen, OC₁₋₄alkyl.
 4. A compound according to claim 3 wherein R1, R2, R3, R4, R5,R6, R7, R8, R10 are each independently selected from H, C₁₋₄ alkyl,OC₁₋₄ alkyl, CO₂H, CN; R11 and R12 are each independently selected H,C₁₋₄ alkyl.
 5. A compound having the general formula III:

wherein R1, R2, R3, R4, R5 and R6 are each independently selected fromH, halogen, NO₂, CN, CF₃, aryl, heteroaryl, cycloalkyl,cycloheteroalkyl, OCF₃, OR18, SR18, OC₁₋₆ alkyl, OC₂₋₆ alkylNR18R19,Oaryl, Oheteroaryl, Ocycloalkyl, Ocycloheteroalkyl, OC₁₋₆alkylaryl,OC₁₋₆ alkylheteroaryl, OC₁₋₆alkylcycloalkyl, OC₁₋₆ cycloheteroalkyl,CO₂R18, C₁₋₆ alkylCO₂R18, CONR18R19, C₁₋₆ alkylCONR18R19, NR18R19, C₁₋₆alkylNR18R19, NR20C₁₋₆alkylNR18R19, C₁₋₆ alkylNR20Cl_(—)6 alkylNR18R19,NR18COR19, Cl_(—)6 alkylNR18COR19, C₁₋₆ alkylNR20CONR18R19,NR20CONR18R19, C₁₋₆ alkylNR18SO₂R19, NR18SO₂R19; R18, R19 are eachindependently selected from H, C₁₋₄ alkyl, C₁₋₄ alkyl cycloheteroalkyl,aryl, heteroaryl, C₁₋₄ alkyl aryl, C₁₋₄ alkyl heteroaryl, or may bejoined to form an optionally substituted 3-8 membered ring optionallycontaining an atom selected from O, S, NR21; R20, R21 are eachindependently selected from H, C₁₋₄ alkyl; R7 is selected from H, CF₃,aryl, heteroaryl, cycloalkyl, cycloheteroalkyl, CO₂R18, C₁₋₄alkylCO₂R18,CONR18R19, C₁₋₄ alkylCONR18R19, NR18R19, C₁₋₆alkylNR18R19, NR20C₁₋₄alkylNR18R19, C₁₋₆alkylNR20C₁₋₄ alkylNR18R19, NR18COR19,C₁₋₆alkylNR18COR19, C₁₋₆alkylNR20CONR18R19, NR20CONR18R19,C₁₋₆alkylNR18SO₂R19, NR18SO₂R19 wherein R18, R19 are as defined above.6. A compound according to claim 5 wherein R1, R2, R3, R4, R5, and R6are each independently selected from H, halogen, OH, OC₁₋₄ alkyl, C₁₋₄alkyl; R7 is selected from H, C₁₋₄ alkyl, C₁₋₄ alkylCO₂H.
 7. Thecompound of formula V:


8. A pharmaceutical composition comprising (a) one or more compoundsaccording to claim 1; (b) a pharmaceutically acceptable diluent.
 9. Amethod for treating an autoimmune disease involving Fc receptor activitycomprising administering to a subject in need of treatment with one ormore compounds according to claim
 1. 10. A method according to claim 9wherein the autoimmune disease is selected from the group consisting ofrheumatoid arthritis, immune thrombocytopenia purpura, systemic lupuserythematosus and Crohn's disease.
 11. A method for obtaining a compoundwhich modulates Fc receptor activity, the method comprising: (a)providing or designing one or more compounds having structuralcharacteristics to fit in the groove of the FcγRIIa structure; and (b)screening the one or more compounds for modulating activity on the Fcreceptor.
 12. A method according to claim 11 wherein step (a) comprisesfunctionalising the one or more compounds with one or more substituentgroups.
 13. A method according to claim 11 wherein the compounds arescreened by a FcγRIIa dependent platelet activation assay and/oraggregation assay where platelets are activated using heat aggregatedhuman immunoglobulin G as an immune complex.
 14. A compound whichmodulates Fc receptor activity obtained by the method of claim
 11. 15. Amethod for treating an autoimmune disease involving Fc receptor activitycomprising administering to a subject in need of treatment with acompound having the general formula IV:

wherein R1, R2, R3, R4, R5 and R6 are each independently selected fromH, halogen, NO₂, CN, CF₃, aryl, heteroaryl, cycloalkyl,cycloheteroalkyl, OCF₃, OR18, SR18, OC₁₋₆ alkyl, OC₂₋₆ alkylNR18R19,Oaryl, Oheteroaryl, Ocycloalkyl, Ocycloheteroalkyl, OC₁₋₆alkylaryl,C₁₋₆alkylheteroaryl, OC₁₋₆alkylcycloalkyl, OC₁₋₆cycloheteroalkyl,CO₂R18, C₁₋₆ alkylCO₂R18, CONR18R19, C₁₋₆ alkylCONR18R19, NR18R19, C₁₋₆alkylNR18R19, NR20C₁₋₆alkylNR18R19, C₁₋₆ alkylNR20C₁₋₆alkylNR18R19,NR18COR19, C₁₋₆ alkylNR18COR19, C₁₋₆ alkylNR20CONR18R19, NR20CONR18R19,C₁₋₆alkylNR18SO₂R19, NR18SO₂R19; R18, and R19 are each independentlyselected from H, C₁₋₄ alkyl, C₁₋₄ alkyl cycloheteroalkyl, aryl,heteroaryl, C₁₋₄ alkyl aryl, C₁₋₄ alkyl heteroaryl, or may be joined toform an optionally substituted 3-8 membered ring optionally containingan atom selected from O, S, NR21; R20, R21 are each independentlyselected from H, C₁₋₄ alkyl.
 16. A method according to claim 15 whereinR1, R2, R3, R4 are each independently selected from H, halogen, NO₂,OC₁₋₄alkyl, C₁₋₄alkyl R5 is selected from H, Cl, OC₁₋₄alkyl,C₁₋₄alkylaryl, OC₃₋₆cycloalkyl; R6 is selected from CO₂H, CONR7R8; R7,R8 are each independently selected from H, 5-tetrazole.
 17. A method fortreating an autoimmune disease involving Fc receptor activity comprisingadministering to a subject in need of treatment a composition accordingto claim 8.